Volume 5 — DISEASES OF THE NERVOUS SYSTEM. (continued 12)

Further, very many chronic diseases produce neurasthenia. It has not been many years since general debility was a common inscription upon records of diagnosis. In very many cases the general debility afflicted the diagnostic powers or zeal of the physician rather than the body of the patient, and it is to be feared that neurasthenia not rarely at present replaces it. Malarial poisoning, chronic Bright's disease, chronic diarrhœa, lithæmia, and various other affections may be readily overlooked, and patient and physician satisfied with the diagnosis of neurasthenia; indeed, in my own experience in a very considerable proportion of the cases which had been diagnosed as nervous exhaustion the patient was really suffering from definite disease.

The folly of attempting to make neurasthenia a distinct affection is strongly brought out whenever it is attempted to give sharp diagnostic differences between it and other diseases. As examples may be noted the flat contradictions which exist in the different diagnostic tables given in the elaborate work of the late George M. Beard.

It is necessary, therefore, in the outset, to recognize that neurasthenia is a bodily condition which is very frequently associated with various chronic disorders, or not rarely coexists with perverted functional activity of the nervous centres, which perverted nerve-functions may, however, exist independently of any perceptible neurasthenia, and are not simply the outcomes of the neurasthenia. Under these circumstances an apology for devoting an article in this work to the consideration of neurasthenia may seem necessary to readers. The justification of the present discussion is to be found in the facts that neurasthenia often exists without the presence of definite disease, and that still more frequently it is a bodily condition which dominates in its therapeutic importance the manifestations of perverted functions, so that the patient is to be treated for it rather than for the disease with which it is associated.

ETIOLOGY.—There are various chronic diseases which may lead directly to nervous exhaustion. Neurasthenia may, moreover, be the result of disease which is long past; neglected diarrhœas, bleeding piles, and other affections with exhausting discharges, when they have been cured, may leave behind them conditions whose source and nature it is most important to recognize.

Overwork, excessive mental emotion, need only to be alluded to as capable of producing a pure neurasthenia. As Samuel Jackson was accustomed to say, in his lectures at the University of Pennsylvania thirty years ago, “Whenever the expenditure of nerve-force is greater than the daily income, physical bankruptcy sooner or later results.” It is to be remembered that the nerve-capital of persons differs almost as widely as does their moneyed capital. There are numerous families many of whose members are neurasthenics from birth—i.e. who are born with less power of creating nervous energy than is necessary to meet the requirements of the ordinary duties of life. There is every grade of natural endowment between the most feeble person, scarcely able to produce more nervous energy than is necessary for breathing, eating, and drinking, and the organism that is capable of enduring incessant toil. The development of neurasthenia is therefore not so much the result of a strain which is absolutely great as of a strain which is excessive in its relations to the organism which has to bear it.

SYMPTOMS.—The onset of neurasthenia is always gradual, although at times the condition appears to develop with great suddenness. Under these circumstances, however, the explosion has been preceded by a long train of more or less overlooked phenomena: thus, in a case that just now occurs to me a gentleman had long suffered from the premonitory symptoms of neurasthenia, to which he had paid but little attention until he was one day seized with violent vertigo, accompanied by such prostration of strength that he had to be taken home from the street in a carriage. The symptoms vary very much according to the portion of the nervous system which is especially affected, and also to some extent according to the etiology of the attack. Nervous exhaustion may in the beginning affect the whole of the nervous system, or it may be at first purely local and coexist with general nervous strength. Many cases of spermatorrhœa are instances of the local form of neurasthenia, the sexual centres being primarily affected; but as in these cases, sooner or later, the whole of the nervous system becomes implicated, so in other forms of the disorder the exhaustion, at first local, finally, if neglected, implicates the whole organism. There are not rarely cases of brain exhaustion in which the symptoms are at first purely local. Almost always the cause of a local neurasthenia is excessive use of the part; thus, cerebral asthenia is usually the result of mental overwork, sexual asthenia of sexual excesses, etc. When to the intellectual fatigue is added the depressing effects of excessive anxiety or allied emotions, the symptoms usually from the first are more general. The exhaustion may affect chiefly a single function of the brain. As an instance may be cited the case of a postal clerk now under my care, who has been accustomed to distribute five to eight thousand letters every day from a general mass into three hundred pigeon-holes representing as many post-office districts scattered over a large territory. As soon as the address is read there must be an instantaneous automatic recognition of the district to which the letter goes. It is at this place where, in the case now under consideration, the symptoms manifest themselves. Reading the address fails to produce immediate recognition of the locality to which the letter is to be assigned. Asked in what district such a post-office is, the clerk answers instantly, but seeing the address himself he hesitates, and sometimes balks so that he can distribute only about one-third as many letters as when in health. As in most cases of local nerve exhaustion, in this patient some evidences of general implication exist, there being decided disturbance of the sexual organs.

Another form of local neurasthenia which is frequently associated with brain exhaustion is that of writer's cramp. I have repeatedly seen it come on as the herald of a general breakdown; but under such circumstances the symptoms have usually not been those of typical writer's cramp: there have usually been not so much marked spasms as loss of power and distress in the arm on attempting to write.

In pure brain exhaustion loss of the disposition to work is usually the first symptom, the sufferer finding that it constantly requires a more and more painful effort of the will to perform the allotted task. The basis of this difficulty is largely loss of the power of fixing the attention, and this by and by is accompanied with weakness of the memory. Disturbances of sleep are frequent. Various abnormal sensations in the head are complained of. In most cases there is not absolute headache, but a feeling of weight or fulness or an indescribable distress, usually aggravated by mental effort.

It is true that in some cases of very dangerous brain-tire cerebration is performed with extraordinary vigor and ease; the power of work is for the time markedly increased, and even the quality of the product may be raised; the patient may even glory in a wild intellectual exaltation, a sense of mental power, with an almost uncontrollable brain activity. It is probable, however, that these cases are not instances of pure neurasthenia, but that there is an active congestion of the cortical gray matter. It is certain that they are very prone to end in serious organic brain trouble. In some cases of cerebral asthenia there are disturbances of the special senses, tinnitus aurium, flashes of light, and even the seeing of visions. Under these circumstances it is again probable that active congestion of the affected centres exists.

Severe cerebral neurasthenia may be associated with good spirits, but usually there is marked depression, and this perversion of function may finally go on to decided melancholy. The will-power, as all other functional activities of the brain, is prone to be weakened; morbid fears may finally develop themselves; and at last that which was at the beginning a simple brain exhaustion may end in hypochondriasis or insanity. In my own experience such ending is very rare unless there have been from the beginning marked symptoms of hypochondriasis or melancholy; in other words, unless there be the inborn tendency to distinct mental disorders, cerebral neurasthenia rarely produces them, but in a person who inherits such tendency the brain exhaustion may become an exciting cause of insanity.

The symptoms of brain-tire may be very largely existing in the individual who still has muscular strength and is capable of enduring much physical labor; but in most cases, sooner or later, the more general symptoms of neurasthenia manifest themselves.

Amongst the earliest of these symptoms may be disorder of the special senses. For reasons which are not very evident it is the eye which is generally affected. Although existing deafness is often greatly intensified by the coming on of nervous exhaustion, I cannot remember ever to have seen severe deafness entirely neurasthenic. The nature of the optical trouble is to be recognized by the fact that vision is at first good, but fails when the eye is steadily used for a few minutes, although the organ is physically perfect. This weakness of the eye may long be the most troublesome manifestation of the disorder.

In some instances, before any loss of muscular strength is marked, vaso-motor weakness is prominent. Excessive blushing on the slightest provocation, great flushing of the face after the use of alcohol or other stomachic irritant, waves of heat passing over the body, occasional pallors provoked by exertion or apparently causeless, and cold extremities, are some of the phenomena which mark the lack of power in the centres that control the blood-vessels. Closely allied to these disturbances are those of secretion. In my own experience the most marked of these is a tendency to night-sweats, but in some cases the hands, and more rarely the palms of the feet, are perpetually bathed in perspiration, which may be greatly increased by any emotional disturbance. In some patients there is a very great tendency to serous diarrhœa, which in its turn of course increases the nervous exhaustion.

In many neurasthenics the heart as well as the vaso-motor system sympathizes in the weakness, so that palpitation and shortness of breath not rarely follow even slight exertion: a more characteristic symptom is, however, a peculiar dropping of the heart's beat, which is to the patient at first very alarming, but which is entirely independent of any lesion of the heart itself. The true nature of this cardiac intermission is to be recognized by the existence of other symptoms of neurasthenia, and by the fact that it is not constant, and that it is very prone to follow eating or gastric irritation of any kind. Not rarely it is relieved at once by the belching up of wind. When tobacco has been very freely used the cardiac symptoms of neurasthenia usually come on very early, and may be very severe. Under these circumstances it is really a mixture of neurasthenia and tobacco-poisoning with which we have to deal.

The muscular strength may finally fail almost altogether. It is almost characteristic that the patient should be capable of much exertion under excitement, and should suffer from the results of such exercise not immediately, but after one or two days.

In many cases of neurasthenia atonic dyspepsia exists, but it is always a question for careful consideration how far a nervous condition is due to the dyspepsia and how far the dyspepsia is caused by the nervous condition.

Disturbances of sensation are common in neurasthenia, these disturbances taking the form in many instances of itchings or formication or other similar minor ills. Neuralgia is often severe and its attacks frequent, but I am convinced that something more than simple nervous exhaustion is responsible for its production. I believe that there is a neuralgic diathesis or temperament which is often associated with neurasthenia, but may exist without it, and which probably has, at least on many occasions, relations to a gouty ancestry. When such temperament exists the neuralgic attacks are greatly aggravated by the coming on of neurasthenia. Hyperæsthesia and anæsthesia mark the line where simple neurasthenia passes into hysteria. The same also is true of the peculiar tenderness over the spinal processes of the vertebræ, which is especially frequent in women, and is the chief symptom of the so-called spinal irritation or spinal anæmia—an affection which I believe to be a form of neurasthenia allied to hysteria.

In neurasthenia disturbances of the sexual organs are very common; in women great pain on menstruation, ovarian irritation, the so-called irritable uterus of Hodge, are closely connected with a general nerve weakness. In not a small proportion of the cases of uterine disorders which are often locally treated I believe the local disease is largely the expression of the general condition. It is well known that masturbation and sexual excess in the male may produce an exhaustion of the nerve-centres especially implicated and also a general nervous exhaustion. This is the common history of spermatorrhœa. It is no less true that a general neurasthenia may produce a local weakness of the sexual centres, with symptoms at least resembling those of spermatorrhœa—namely, great irritability of the sexual organs, with a practical impotence due to immediate seminal discharge whenever coition is attempted. I have certainly seen this condition result from excessive intellectual labor when there has been no sexual excess, and at a time when the muscular strength was still good. Such cases may, perhaps, be distinguished by the fact that unprovoked emissions are not nearly so apt to occur as in true spermatorrhœa.

TREATMENT.—The natural cure for neurasthenia is rest, and my own experience coincides with the logical inferences to be drawn from an etiological consideration of the subject—namely, that medicines are only of limited value, and unless very judiciously administered may readily do harm. Disturbing symptoms should be met and tonics may be used, especially strychnine and arsenic, but all drugs hold a secondary position in the relief of a pure neurasthenia. In using remedies the practitioner must be guided by general principles, and I shall not engage in any detailed consideration of the subject, but employ the space at my disposal with a discussion of rest.

When nervous exhaustion has been produced by over-use of any one organ or system of organs, absolute rest of such organ is a primary necessity. Thus, when there has been sexual excess absolute avoidance of use of the sexual organs must be enjoined, and in married Americans it is often essential to insist upon man and wife occupying distinct apartments¹ or even to separate them by a journey.

¹ Because in this country man and wife habitually occupy one bed. Sexual continence under these circumstances can only be obtained at the cost of a suppressed sexual excitement worse than moderate indulgence.

Again, in cases of brain-tire it is the brain which should be rested. To rest an overwearied, excited brain is often not an easy task. In attempting it the effort should be to obtain the following results: 1st. The removal of all cares, anxieties, and all brain-work, especially those of such character as have been connected with the breakdown. 2d. The maintenance of the interest of the patient, so that the past shall for the time being be forgotten, and the present not overweighted with irksomeness. 3d. Invigoration of the physical health of the whole body, and especially of the nervous system. In order to obtain the first of these measures of relief, isolation of some sort is essential; for the second mental occupation is usually required; for the third fresh air, exercise, or some substitute is to be superadded to abundant food and rest.

The proper method of meeting these indications varies greatly, not only with the varying physical conditions and idiosyncrasies of patients, but also with their diverse domestic and pecuniary relations. To give detailed directions for every case is impossible, and I shall therefore limit myself first to simple cases of brain-tire in which the muscular strength is preserved; second, to cases of profound general neurasthenia.

In brain-tire travel is usually recommended, and travel affords, when properly directed, separation from old cares and thoughts, a maintenance of interest by a succession of novel sights and experiences, and the physical stimulation of fresh air and exercise. In bad cases general travel is too stimulating, and ocean-voyaging is much better. Upon the ocean is to be found nothing provocative of thought, only complete isolation, fresh air, enjoyment if the patient be fond of the sea, and a sufficient exercise, especially if the sufferer in any large measure works in the management of a sailing vessel. Hence prolonged yachting affords in many cases our best method of relief. The isolation of the North Woods or any other large primeval wilderness may be complete, the air most fresh, and the exercise to be had also boundless, but at the same time controllable; the man may, according to his will, lie in his tent and be fed by his guide or be unceasingly active. If the life be agreeable to the sufferer, and sufficient care against undue exposure be exercised, the camp-cure is most efficient. European travel may serve almost equally well, provided hard journeying, sight-seeing, and even cities are avoided. The quiet of Switzerland or the Tyrol may bring restoration when the bustle of London and Paris might complete the ruin.

To those who cannot travel extensively the seashore, mountains, or lowlands of the United States are open, and the best way of meeting the indications in any individual case must be determined by a joint consultation between doctor and patient.

There are cases of neurasthenia in which the slightest exercise does harm, and in which even the unconscious effort of company and conversation is an injury. Between the extremely exhausted and the slightly brain-tired is every grade of case, and much tact is often required in properly regulating the treatment of the individual case.

It is only the most severe forms of neurasthenia which require the use of the so-called rest-cure. For such, however, it is a very valuable method of treatment. It finds its most brilliant application undoubtedly in neurasthenic women, but, more or less modified according to circumstances, it has a wide scope in the treatment of both sexes. When the bodily condition is developed by prolonged lactation, nursing, grief, overwork, acute disease, or other temporary or removable cause, the rest-cure may give permanent relief; and even when the cause of the neurasthenia is largely inherited feebleness of constitution, it is a valuable though a more temporary remedy. This method of treatment has long been used in this city, and was especially dwelt upon in its general scope by Samuel Jackson, but in its modern form it has become a very valuable method of treatment, essentially different in its details from what it was formerly, and far more potent in its influence. To S. Weir Mitchell is due a great debt of gratitude, for by him has this improvement been made.

The principles of the rest-cure are absolute rest, forced feeding, and passive exercise. Absolute rest is often prescribed by the physician without being sufficiently definite and insisted upon. When it is desired to apply it most strictly, it should be clearly explained that the patient is not to be allowed to get out of bed even to pass urine or feces, not to feed himself or herself, or perform any act of the toilet whatsoever. The rest also must be for the mind as well as for the body, and it is essential that the patient be isolated. Separation from friends should especially be insisted upon in the case of women. It may be possible to separate a man in his own house completely from his daily cares, but a woman in her own house is in the midst of her daily business, and is like a man placed in the corner of his factory. In obstinately severe cases of neurasthenia complete and absolute isolation is a sine quâ non, and especially when there is a decidedly hysterical element is it necessary to separate the patient entirely from her friends. Under these circumstances there must be a well-trained nurse who is personally agreeable to the patient. The confinement would be very irksome to any except the most exhausted patient were it not for the daily visit of those engaged in the treatment; to further provide against ennui the nurse should be a good reader, so that under the definite instructions of the physician she can occupy a certain portion of the time in reading to the patient.

In order to maintain the functions of the skin the patient should be well sponged in bed every morning after breakfast. A strong solution of salt, or, better, sea-brine, is to be preferred to simple water, and frequently it may be followed by the use of alcohol. In very feeble cases the alcohol may be employed alone. I have seen very good effects from momentarily rubbing each portion of the skin with ice just after the bathing.

The question of feeding is one of great importance, and requires the utmost care and attention from the physician. The end to be attained is to feed the patient as much as can be digested, but not to overdo and derange the digestion. Food should be given at intervals of two or three hours, and must be both light and nutritious. It should, at least at first, largely consist of milk, except in those rare cases in which that fluid does really disagree, and not merely is thought to do so. The milk should be skimmed or given in the form of koumiss. Beef and other concentrated meat-essences are valuable as stimulants, and may be used, especially as the basis of soups. Various farinaceous articles of food may be added to them, or if an egg be broken into the concentrated bouillon or beef-essence just as it ceases boiling a nutritious, and to many persons palatable, dish is obtained. When constipation exists, oatmeal porridge, Graham bread, fresh or dried fruits may be allowed if readily digested by the patient. In order to give an idea of the general plan of the dietary, the following schedule of the daily life is given. Such a schedule should always be put into the hands of the nurse, who should be required to follow it strictly. It must be altered from day to day, so as not to weary the patient with monotony. It is especially important to remember that the diet must be carefully studied for each patient, and be adapted to the individual requirements of the case. Success will in a great measure depend upon the practical skill and tact of the physician in this adaptation:

8 A.M. Rolls or toast; cocoa or weak coffee, or roasted wheat coffee; beefsteak tenderloin or mutton chop.

9 A.M. Bathing.

11 A.M. Oatmeal porridge, with milk, or else a pint of koumiss.

12 M. Massage.

2 P.M. Dinner: Bouillon with or without egg; beefsteak; rice; roast white potatoes; dessert of bread pudding, blanc mange, or similar farinaceous article of diet.

4 P.M. Electricity.

5 P.M. Milk toast.

9 P.M. Half pint of skimmed milk or koumiss.

In many cases the patient at first can take very little food, and it is very frequently best to begin the treatment with an entirely liquid diet, giving milk every two hours, or using Liebig's raw-meat soup, with milk or plain farinaceous food, and only after a time gradually accustoming the patient to solid food. Not rarely a prolonged treatment by the so-called milk diet is of avail. The rest-cure is indeed largely based upon a careful regulation of the food; but a full discussion of the various dietaries to be used would require a treatise upon dietetics.

Passive exercise is to be obtained by the use of electricity and massage, the object being to get the effects of exercise upon the nutrition and circulation without the expenditure of the patient's nerve-force. By the use of electricity muscular contractions are secured which simulate those which are voluntary and more or less thoroughly replace them. By the general application of the current to the whole body we probably affect the tone of all of the minute blood-vessels, and certainly in this or some other way stimulate the general nutrition, and, as has been shown by S. Weir Mitchell, for the time being elevate the bodily temperature.

The faradic current is alone used. It is applied in two ways: first, to the individual muscles; second, to the whole body. The séances should be daily, the operator beginning at the hand or foot, and systematically faradizing each muscle of the extremities and trunk.

The slowly-interrupted current is generally preferable, but advantage is sometimes gained by varying the rapidity of the interruptions. The general rule is to select that current which produces most muscular contraction with the least pain. The poles should be applied successively to the motor points of the muscles, so as to contract each firmly and thoroughly. This process should occupy from thirty to forty minutes. The electrodes are then to be replaced by large sponges well dampened with salt water: one of these should be put at the nape of the neck and the other against the soles of the feet, and a rapidly-interrupted current, as strong as the patient can bear, should be sent through the body for twenty minutes or half an hour. It is not necessary for the operator to remain during this time. In some cases the electrical programme may be varied so as to get a local stimulant action from the general current; thus, when digestion is enfeebled and the bowels costive for a portion of the time one of the sponges may be placed upon the epigastric region. In women when there is great abdominal and pelvic relaxation one pole may be placed high up in the vagina. I have seen old-standing prolapses cured in this way. Some electro-therapeutists claim great advantage from galvanization of the cervic sympathetic ganglia, but I do not myself believe that they ever succeeded in reaching these ganglia with the current.

Massage, like electricity, affects greatly the peripheral circulation, empties the juice-channels, and gives tone to the muscular system. It must be clearly distinguished from rubbing of the skin. It consists in manipulations of such of the muscles as are not too deep to be reached, and of the cellular tissue: in order to lessen as much as may be the skin friction by these manipulations, it is often well to anoint the surface with cocoanut or other bland oil. As sold in the drug-stores, cocoanut oil is very often rancid, and at any time it is well substituted by the cheaper cottonseed oil. In practising massage it is essential to remember that the natural course of the venous blood and the juices of the cellular tissue is toward the centre of the body; therefore, all general movements should be practised in this direction.

The manipulations are percussion, rolling, kneading, and spiral. They consist of movements made with the pulpy ends of the fingers and thumbs, and spiral movements with the whole hand so folded as to adapt its palm to the limb. In percussion the strokes should be from the wrist, and should be quick and short. It is probably not possible, even by long strong strokes, to affect deep muscles. In the rolling manipulation the effort is to roll the individual muscles beneath the pulps of the fingers. This manipulation may be varied by pinching the muscles, not the skin, and kneading. In each case it is intermittent pressure upon the muscles which is aimed at. The circular movements are to be in opposite directions with both hands simultaneously, the limb being grasped by one hand a little above the other, and a spiral sweep made up the limb, the ball of the thumb and the palm of the hand resting upon the patient, and the pulpy parts of the thumb and the fingers grasping the limb. It is especially such motions as these which affect the circulation of the flesh-juices.

The length of time the patient is to be kept in bed and treated in the manner described varies of course with the individual case, but usually less than four weeks is not sufficient, and rarely are more than six weeks required. In getting up, the patient should begin by sitting up one or two hours a day, increasing daily, but not too rapidly, the time of being out of bed and the amount of exertion made. The electrical treatment should be gradually intermitted: in many cases massage twice a week seems to be of service even after the patient is about. In the going back to ordinary daily life great care is to be exercised to proportion the amount of exertion to the newly-obtained strength, so as not to lose what has been gained. In cases of natural or of long-standing acquired severe neurasthenia the mode of life must be arranged to correspond with the small daily product of nervous energy.

In dismissing this subject I desire to caution against a routine employment of this so-called rest-cure, which might readily degenerate into a species of quackery; and, again, to call attention to the widespread value of the principles which underlie it, and the importance of the physician applying those principles with endless modifications of detail.

SLEEP, AND ITS DISORDERS.

BY HENRY M. LYMAN, A.M., M.D.

The regularly-recurring incidence of natural sleep forms one of the most important subjects of physiological investigation. Occurring ordinarily at stated intervals connected with the diurnal revolution of the earth, it may for a time be postponed by an effort of the will, but an imperious necessity for repose finally overcomes all opposition, and the most untoward circumstances cannot then prevent the access of unconsciousness. Thus produced, the relation of cause and effect between weariness and sleep becomes very apparent. The refreshing influence of such repose points clearly to the restorative character of the physical processes that continue despite the suspension of consciousness; it also renders evident the final cause of that periodical interruption of activity which the brain experiences in common with every other living structure.

Careful observation of the manner in which sleep invades the body indicates that its evolution is not associated with a simultaneous suspension of every mode of nervous function. The sense of sight is the first to yield. The eyelids close and the muscles that support the head give way. The body seeks a recumbent position; quiet and seclusion are instinctively sought. The purely intellectual faculties are not yet depressed, and the reflex energies of the spinal cord are exalted. Soon, however, the other senses fail; hearing persists the longest of all. Released from the control of external impressions, the internal senses preserve their functions after a strangely-disordered fashion, dependent upon the progressive suspension of activity in the various cerebral organs. First the power of volition ceases; then the logical association of ideas comes to an end. Presently the reasoning faculties disappear, and judgment is suspended. We thus become no longer capable of surprise or astonishment at the vagaries of memory and imagination, the only mental faculties that remain in action. To their unrestrained function we owe the presentation in consciousness of the disorderly picture which we call a dream. During the early stages of this somnolent state we often remark the fact of dreaming, and an effort at attention may produce a partial awakening; but usually the subsidence of cerebral function is progressive and rapid. The fire of imagination fades; the field of consciousness becomes less and less vividly illuminated; the entire nervous apparatus yields to the advancing tide; and, finally, the dominion of sleep is fully confirmed.

During the act of awaking the order of sequences is reversed. From the end of the first hour of repose the depth of sleep, at first rapidly, then more gradually, diminishes.¹ Dreams disturb its quiet, mental activity increases, the power of volition revives; once more the individual is awake.

¹ Kohlschütter, Messungen der Festigkeit des Schlafes, Dissert., Leipzig, 1862, and Zeitschr. f. Rat. Med., 1863.

Sleep, then, is that condition of physiological repose in which the molecular movements of the brain are no longer fully and clearly projected upon the field of consciousness. This condition is normal, and must, consequently, be differentiated from all pathological states which produce its counterfeit by the more or less complete abolition of consciousness. This distinction becomes the more necessary because the presence of the common factor, unconsciousness, in the result has frequently led to the mistake of supposing a community of antecedents in the changes by which the passage from sensibility and consciousness to insensibility and unconsciousness is effected. It needs no argument to show that the insensibility of artificial anæsthesia is a very different thing from the unconscious condition which obtains during natural sleep. Between the stupor of intoxication and the healthful restoration of cerebral energy which accompanies genuine sleep there can be no rational comparison. It is therefore in the phenomena of syncope that the likeness of sleep has usually been sought. The well-known fact that a copious hemorrhage can speedily develop a condition of muscular relaxation, insensibility, and unconsciousness has led certain observers to the belief that natural sleep is, after all, only a species of physiological syncope. The antecedent conditions of syncope are so different from the prodromata of sleep that it is difficult to see how either state can be properly likened to the other. The bloodless condition of the brain which occasions syncope is always the result of pathological or accidental causes, and is not identical with the comparatively insignificant reduction of blood-pressure which may be observed in the brain of the healthful sleeper. It is, moreover, worthy of note that sleep is the normal condition of the unborn child, despite the fact that the growing brain receives a richer supply of oxygenated blood than the trunk and the lower limbs—a state of the circulation quite unlike that of syncope.

Fully impressed by the force of such considerations, certain physiologists² have reasoned from the analogies suggested by the results of muscular fatigue, and have imagined an hypothesis accounting for the occurrence of sleep by a supposed loading of the cerebral tissues with the acid products of their own disassimilation during wakeful activity. The acid reaction of the brain and of the nerves after exertion suggested the probability that an excessive presence of lactic acid and its sodic compounds might be the real cause of cerebral torpor and sleep. Could the hypothesis be proved, ordinary sleep would take its place in the anæsthetic category and sodic lactate should be the very best of hypnotic agents. Unfortunately for this doctrine, the administration of the lactates has yielded only the most contradictory and unsatisfactory results. It, moreover, furnishes no explanation of intra-uterine sleep nor of the invincible stupefaction produced by cold.

² Obersteiner, “Zur Theorie des Schlafes,” Zeitschr. f. Psych., xxix.; Preyer, “Ueber die Ursachen des Schlafes,” Vortrag. Stuttgart, bei Enke, 1877; and Centralbl. f. d. Med. Wiss., 1875, S. 577.

Far more comprehensive is the hypothesis of Pflüger.³ According to this view, the cortical tissues of the brain are recruited by the assimilation of nutrient substances derived from the blood. By this process oxygen is stored up in chemical combination, forming explosive compounds whose precise composition is not fully understood. Under the influence of the various nervous stimulations that reach the brain these unstable compounds break up into simple forms. The motion thus liberated by these explosions is, in some way at present utterly unintelligible to us, projected into the field of consciousness where the mind dwells, and we are thus brought into conscious relation with the external world. That the capacity for thus signalling across the gulf which separates matter from mind is the result of a certain perfection and complexity of material structure is rendered probable by the utter failure of the infracortical organs of man to impress the conscious intelligence by any amount of independent activity. It is also indicated by the unconscious sleep of the rudimentary fœtal brain and by the brevity of the intervals of wakefulness which mark the life of the new-born babe. That this capacity is dependent upon the mobility of the atoms of the brain is shown by the speedy cessation of intelligence which follows great reduction of temperature, as in hibernation or during exposure to severe frost. That its exercise is largely dependent upon the activity of the senses is proved by the effects of interference with their function. A recent observation, recorded by Strümpell,⁴ is very significant in this connection: A young man had lost all power of sensation excepting through the right eye and the left ear. A bandage over the eye and a plug in the ear arrested all communication between his brain and the external world. Thus imprisoned within himself, he gave utterance to an expression of surprise, and sought in vain, by clapping his hands, to arouse the sense of hearing. At the end of two or three minutes these efforts ceased; respiration and pulsation were deepened and retarded, and removal of the bandage exhibited the patient with his eyes closed in genuine sleep.

³ “Theorie des Schlafes,” Arch. f. d. Ges. Physiol., x. 468.

⁴ “Beobachtungen ueber ausgebreitete Anästhesien und deren Folgen,” Deutsch. Arch. f. klin. Med., xxii.

The dependence of the waking state upon the presence and functional activity of a sufficient quantity of a peculiarly unstable form of protoplasm in the brain is an hypothesis which presents no great difficulty of comprehension. But how may we explain the passage from the vivacity of that waking state into the inactivity of sleep? I have elsewhere⁵ discussed the manner in which artificial sleep is produced by impregnation of the brain with anæsthetic substances, and the same general line of argument may be extended to cover the action of every stupefying agent with which the blood may become overcharged. Could the hypothesis of Obersteiner and Preyer be accepted, it would be an easy matter to explain the advent of sleep when it gradually supervenes; but we cannot thus explain the rapid and intentional passage from wide-awakefulness into the profoundest sleep, such as becomes a matter of habitual experience with sailors and with others who have formed the habit of going at once to sleep at regularly-recurring periods of time. Certain writers have endeavored to account for this fact by imagining a special mechanism at the base of the brain (choroid plexuses of the fourth ventricle, etc.), by means of which the current of blood through the brain may be voluntarily diminished, with a consequent arrest of conscious activity. But, still adhering to the hypothesis of Pflüger, we shall find a clearer explanation of the facts by considering the phenomena connected with the succession of impressions upon the organs of sense. It has been ascertained⁶ that such impressions must persist for a certain measurable length of time in order to excite conscious perception. A sound must be prolonged for at least 0.14″, a ray of light must agitate the retina for 0.188″–0.2″, ordinary contact with the surface of the body must continue during 0.13″–0.18″, in order to produce any knowledge of sound and light and common sensation. For the simplest act of perception 0.02″–0.04″ are necessary. It is therefore perfectly reasonable to suppose that when the explosive material of the brain has been sufficiently reduced in quantity and quality by prolonged cerebral effort, the impression of sense may no longer suffice to excite in the cortical substance vibrations of sufficient length, or following each other in sufficiently rapid succession, to sustain the conscious state. The cortex of the brain may then be likened to the surface of a body of water into which bubbles of soluble gas are introduced from below. When the bubbles are large and succeed each other rapidly, the surface is maintained in a state of continual effervescence. But if the size of the bubbles be diminished or if the solvent capacity of the liquid be increased, its surface will become almost, if not quite, perfectly tranquil. In some such way, without any great amount of error, may we picture forth the molecular changes that determine the advent of sleep.

⁵ Artificial Anæsthesia and Anæsthetics, pp. 15-17.

⁶ Carpenter's Physiology, 8th ed., p. 852.

Returning now to the subject of the rapid induction of sleep, we find that it usually occurs among people who lead an active life in the open air, like children and laborers, and are perhaps compelled to endure frequent interruptions of their rest. The sailor who is trained to sleep and to work in rapidly-successive periods of time—four hours on deck and four hours below—has virtually become transformed by this habit into a denizen of a planet where the days and the nights are each but four hours long. His functions become accommodated to this condition; his nervous organs store up in sleep a supply of protoplasm sufficient only for an active period of four or five hours, so that when his watch on deck is ended he is in a state as well qualified for sleep as that of a laborer on shore at the end of a day of twelve or fifteen hours. Moreover, the majority of those who manifest the ability thus to fall asleep are individuals whose waking life is almost entirely sustained by their external perceptions. So soon, therefore, as such excitants are shut out by closing the eyes and by securing shelter against the sounds and impressions of the air, comparatively little remains for the production of ordinary consciousness, and sleep readily supervenes, especially if the excitable matter of the brain has been already depleted by active exertion.

It is well known that a predisposition to sleep may be very quickly induced by extraordinary expenditures of force; witness the effect of the venereal act and the consequences of an epileptic fit. That analogous predispositions may indeed be very rapidly developed by modifications of cerebral circulation is shown by the sudden reduction of cerebral excitability during the act of fainting. But this does not prove that cerebral anæmia should be elevated to the rank of the principal cause of natural sleep. In all such cases the nervous process is the primary factor and the direct cause of change in the circulation.⁷ The character of these changes has been admirably illustrated by the observations of Mosso.⁸ By the aid of the plethysmograph this experimenter was enabled to compare the state of the circulation in the human brain, laid bare by erosion of the cranial bones, with the movement of the blood in other portions of the body. The occurrence of sleep caused a diminution in the number of respirations and a fall of six or eight beats in the pulse. The volume of the brain and its temperature were at the same time slightly reduced through the diversion of a portion of the blood-current to other regions of the body. If during sleep a ray of light was allowed to fall upon the eyelids, or if any organ of sense was moderately excited without waking the patient, his respiration was at once accelerated, the heart began to beat more frequently, and the blood flowed more copiously into the brain. Similar incidents accompanied the act of dreaming. The renewal of complete consciousness was followed by an immediate increase in the activity of the intracranial circulation.

⁷ W. T. Belfield, “Ueber depressorische Reflexe erzeugt durch Schleimhautreizung,” Du-Bois Reymond's Archiv, 1882, p. 298.

⁸ Ueber den Kreislauf des Blutes im menschlichen Gehirn, Leipzig, 1881.

In all these variations it is worthy of note that the nervous impression was the primary event. The changes of blood-pressure and circulation were invariably secondary to the excitement of nerve-tissue. Sleep, therefore, is the cause, rather than the consequence, of the so-called cerebral anæmia which obtains in the substance of the brain during repose. This condition of anæmia is nothing more than the relatively lower state of circulation which may be discovered in every organ of the body during periods of inactivity. Every impression upon the sensory structures of the brain occasions a corresponding liberation of motion in those structures. The movement thus initiated arouses the vaso-dilator nerves of the cerebral vessels and excites the vaso-constrictor nerves of all other portions of the vascular apparatus. Hence the superior vascularity of the brain so long as the organs of sense are fresh and receptive; hence the diminishing vascularity of the brain as its tissues become exhausted and unexcitable; hence the unequal and variable vascularity of different departments of the brain as sleep becomes more or less profound. These modifications of the brain and of its circulation are well illustrated by the effects of a moderate degree of cold applied to the cutaneous nerves of the body, as not infrequently happens when the night air grows cool toward morning. Such moderate refrigeration of the skin excites its sensitive nerves, which transmit their irritation to the brain. The excitement of this organ causes dilatation of its vessels, with increased irritability of the cortex, vigorous projection into the field of consciousness, and the consequent occurrence of dreams denoting imperfect slumber or even complete awakening. The remedy consists in the application of gentle heat to the surface of the body. By this means the transmission of peripheral irritation is checked; the brain becomes tranquil; sleep supervenes. A similar wakefulness is in like manner produced by unusual heat. The remedy here consists in the employment of measures calculated to reduce the temperature of the skin to the normal degree. Sometimes wakefulness is maintained by some less general irritant. The feet alone may be cold, either because of previous refrigeration or because of local hyperæmia occurring elsewhere in an anæmic subject. There, again, equalization of the circulation—that is, the removal of cerebro-spinal irritation—may be all-sufficient to procure sleep. Noteworthy also is the tranquillizing effect of foot-baths or of the wet sheet in many cases of cerebral excitement and wakefulness. In like manner, that form of sleeplessness which often follows intense mental activity may generally be obviated by a light supper just before going to bed. Activity of the stomach is thus substituted for activity of the brain, and the consequent diversion of blood is sufficient to reduce the production of excitable matter in the brain to a point that permits the occurrence of sleep. A morbid exaggeration of this process is sometimes witnessed in the soperose condition that accompanies digestion in patients whose blood has been reduced by hemorrhage or by disease. In such cases the nutrition of the brain proceeds at so slow and imperfect a rate that any considerable diversion of blood toward other organs produces a syncopal slumber which resembles normal sleep only by the fact of unconsciousness. If, however, food be taken in excessive quantity or of irritable quality, the consequent indigestion will produce nervous excitement, reaching perhaps to the brain, and preventing sleep.

Dreams.

The most interesting question regarding sleep concerns the condition of the mind during repose. We know that while the body is awake the mind is always active: does this activity entirely cease during the period of sleep? The phenomena of certain varieties of trance indicate that the mere semblance of death is not incompatible with great mental activity. In like manner, the phenomena of dreams serve to prove that various intellectual processes, such as memory, imagination, attention, emotion, and even volition, may still be exercised while every external avenue of special sense is closed by sleep. The result of the exercise of mental activity under such conditions constitutes a dream. The fact that observers who have made trial in their own persons have always found themselves engaged with the details of a dream when suddenly awakened from deep sleep has been supposed to afford valuable proof of the proposition that the mind is never wholly inactive during the deepest sleep. To say nothing of the significance of certain somnambulic states (double consciousness), in which intelligence evidently exists for a long period of time without leaving any subsequent trace in memory, the mere fact that we remember very few of the events that occupy the mind in dreams cannot be urged against the doctrine of continuous mental action, for we remember very few of the images and ideas that have stirred the depths of consciousness during the waking state. Our recollection of dreams is exceedingly variable. Sometimes we retain in memory all the events of a long and complicated vision, but usually, though entranced by the vivid beauty of the spectacle that unrolls its splendor before the eye of the mind in sleep, and though the intensity of its seeming action may be sufficient to awaken the dreamer, who recalls each incident as he reviews the picture during the first waking moments, the impression soon fades, and the coming day finds him incapable of reproducing a single scene from the nocturnal drama.

The space allotted to this article will not admit a full discussion of the physiology of dreams. A brief reference to the definition of sleep must suffice to indicate what is signified by the process. Sleep does not wholly arrest the functions of the brain. A certain amount of projection into the field of consciousness seems to continue even during the most perfect repose, and the ideas thus aroused form the material of our dreams. Our waking hours are occupied with the ideas and with the associated trains of thought that are presented in consciousness through the action of our several senses. As a consequence of the harmonious function of these senses, correcting and supplementing each other, a continuous process of logical thought is maintained. But along with the procession of ideas which are distinctly conceived by the mind, the field of consciousness is also invaded by a cloud of half-formed perceptions that are too imperfect and too fleeting to occupy the attention. As in the act of sight, though the periphery of the visual field is clouded with a whole world of objects dimly perceived without arresting particular attention, the centre of that field alone presents a clear image before the brain, so the eye of the mind perceives clearly only a few of the impressions which enter the sphere of consciousness. These neglected perceptions, however, are none the less the result of abiding impressions graven in the substance of the brain, from which, through the action of memory, they may at any favorable opportunity re-enter consciousness. It is well known that a suspension of the functions of any portion of the nervous apparatus tends to increase the energy of the remaining organs; consequently, it becomes highly probable that with the arrest of external perception in sleep the activity of certain portions of the brain must be considerably exalted, so that the impressions which they have previously registered may now more clearly reach the seat of consciousness. The probability of this hypothesis is greatly strengthened by numerous facts that lie open to observation. During the first moments that succeed the closing of the eyes mental activity and the power of attention are not diminished, but are rather increased. As the controlling influence of the cerebrum is withdrawn the reflex energy of the spinal cord becomes temporarily exalted. Witness the paroxysms of cough that sometimes harass a sleeping child who has scarcely coughed at all during his waking hours. Witness the voiding of urine in the bed by nervous children during the early hours of sleep. Witness the phenomena of night-terrors, which always occur at the time of night when sleep should be most tranquil.

It appears, therefore, that the harmonious activity of all parts of the nervous system is indispensable to the highest exercise of the conscious mind. Healthy intellectual life is the perfectly-balanced outcome of the complex polygon of forces which has its seat within the brain. But the suppression of certain lines of this polygon does not suppress life, nor does it necessarily destroy consciousness. It only occasions a redistribution of force and a proportionate narrowing of the stream of related ideas. Since the suppression just mentioned is not an absolute quantity, but a variable factor, the polygon of forces in the brain and the corresponding succession of ideas in consciousness must necessarily be in a state of continual change. Accordingly, our dreams are as variable as the clouds that drift upon the currents of the air. As on a hot day in summer, when the steady equatorial draught has ceased to guide the wind, we may observe all manner of local tides in the masses of vapor which arise from the earth, so in sleep, when the guiding influence of the senses is withdrawn from the brain, the ideas that still arise are chiefly dependent upon its automatic and reflex action for their origin and association. Undisturbed by impulses from the external world, the brain seems then more sensitive to impressions that originate within the body. An overloaded stomach, an enfeebled heart, a turgid sexual apparatus, or an irritable nervous ganglion may become the source of irregular and uncompensated movements which may invade the cerebral cortex, and may there set in motion a whole battery of mechanisms whose influence upon consciousness would be quite unnoticed were the external senses in full operation.

Night-Terrors.

The preceding argument will render it easy to comprehend the phenomena of night-terrors. These are commonly observed in young children of a highly nervous temperament before the conclusion of their second dentition. The subjects of the disorder are generally of neurotic descent. Insanity, hysteria, neurasthenia, epilepsy, chorea, and nervous dyspepsia are often discovered among their near relatives. Not infrequently they have been or will become themselves choreic.

The attack is often preceded by symptoms of indigestion, but it may result simply from the commotion of a brain wearied by the excitement and effort of the previous day. The little patient starts up out of an apparently sound sleep crying with alarm, calling for his mother, and staring wildly with every possible expression of terror. Sometimes he springs from his couch and runs headlong into a corner or seeks to hide under the bed, as if escaping from some frightful object. The eyes are open, tears flow, perspiration covers the skin, there is the greatest excitement, and the little one, convulsively clinging to its parent, will not be quieted. Only after fifteen or twenty minutes, as tranquillity gradually returns, does the child seem to recover the power of recognizing his friends. Presently, however, he lies down and falls quickly asleep, waking in the morning without the slightest recollection of the unpleasant event.

Such paroxysms occur during the early part of the night, one or two hours after the child has been put to bed, just at the time when, according to the previously-quoted experiments of Kohlschütter, sleep is passing from its maximum intensity to a lesser degree of depth. This, then, is the time when the controlling power of the sensory apparatus over other portions of the nervous system has already reached its minimum. The spinal centres and those intracranial ganglia which do not share in the full measure of this repose are therefore in a condition of relative exaltation. Disturbances of internal organs consequently produce inordinate excitement of these waking portions of the nervous apparatus. The morbid quality of this excitement is attested both by the history of the patient and by the fact that it does not arouse the whole brain. The distribution of motion in the cerebrum is impeded, so that certain portions of the organ remain asleep while other regions are thrown into a state of tumultuous uproar. Disconnection of these different organs of the nervous system, by withdrawing particular portions from the inhibitory influence of the remaining parts, gives opportunity for violent explosions of nervous force analogous to the convulsions of a headless fowl or to the course of an epileptic paroxysm. Now, in sleep, in somnambulism, in hypnotism, in delirium, in certain stages of intoxication with alcohol or with narcotics, such ungearing of the different nervous ganglia is more or less completely effected. In narcotic and anæsthetic sleep besides the disassociation of ganglia there is paresis of the nervous molecules; hence the phenomena soon merge into insensibility and coma. But in natural sleep, in somnambulism, or in hypnotism there is no toxic paresis; hence the dissociated portions of the brain and nervous system, if aroused, are in a physiological condition to dispense great stores of force. Hence the vividness of certain dreams and the astonishing vigor of particular nervous functions in somnambulism and hypnotism.

Somnambulism.

The phenomena of night-terrors constitute merely a special form of somnambulism, a condition of which the mechanism, so far as the present state of cerebral physiology will permit, has been already suggested. The affection should not be ranked by itself as a particular variety of disease, but should rather be considered a violent perturbation in the cerebral organs of a neurotic subject during the period of sleep. In ordinary dreaming the muscular apparatus usually remains passive, even though the dream be a nightmare or an incubus of the most terrifying character. But when the desires and the emotions are powerfully addressed by the dream, a certain amount of muscular movement may ensue, as when a dog barks in his sleep, or when a child laughs upon his nurse's lap, or when a weary soldier marches on though overpowered by sleep. One night, when parched with thirst during a voyage at sea,⁹ I saw in sleep a sparkling fountain, by the side of which appeared a young girl holding out a cup of cold water. Awakened by the excitement, I found myself sitting up in bed with my right arm extended in the direction of the tantalizing vision: my dream had merged itself in action. In like manner, the victim of night-terrors not only moves his body, but gives vocal expression of his feeling of apprehension and alarm. In like manner, projecting his dream into action, a sleep-walker may arise from his bed; he climbs out of the window and descends to the ground, executing all manner of complicated and dangerous movements; he walks long distances, and finally returns to his couch without waking. In the morning no recollection of the event of the night survives. Again, the movement may be less locomotive in its character. The intellectual faculties chiefly may be aroused, and then only such movements are executed as may be necessary to give expression to the mental process.

⁹ A proclivity to dreaming has often been remarked among the consequences of partial starvation.

Such, then, are the principal characteristics of somnambulism, a state in which dreams are supplemented by more or less complete and appropriate action, ordinarily without subsequent recollection of either dream or action.

The somnambulistic dream generally occurs during or soon after the period of deepest sleep, when the influences of the external world are largely suppressed. Released from the control of its sensory portion, the remainder of the brain awakes and becomes aroused to a condition of functional exaltation. No longer distracted by the recollection of the special senses, the attention is concentrated upon the hallucinations which constitute the dream. In the simpler forms of noctambulism only the automatic locomotive apparatus is awakened, and the sleeper moves in accordance with the impressions derived from habit aided by exaltation of the muscular sense. But in some of the more complicated cases a certain amount of special sensibility seems to exist. The patient is capable of exercising just that amount of sensation which is necessary to accomplish his purpose, though blind and deaf and insensible to every other impression. The more complete the waking of the organs of sense, the closer the resemblance to the condition of ecstasy in which cerebral exaltation is the prominent feature. Accordingly, it sometimes happens that the somnambulist can recall the events of his paroxysm.¹⁰ In such cases the power of recollection is due to the same conditions that control the recollection of our ordinary dreams. We remember very imperfectly, if at all, the dreams that occur during sound sleep, but the visions with which sleep sometimes commences (hypnagogic hallucinations) and those that occupy the period of morning slumber are very easily reviewed in memory, because they are associated with impressions directly derived from the partially-waking organs of sense. Such dreams are therefore chiefly recalled through their association with the train of our waking thoughts. But the dreams of somnambulism and the dreams of night-terrors, and all other visions during profound sleep, are as completely as possible cut off from all connection with the mental activities which arise directly from the action of the senses. By reason of such isolation the ordinary association of ideas affords no help to the memory, and the dream remains in the limbo of oblivion.

¹⁰ A. Bertrand, Traité du Somnambulisme, p. 80.

Alfred Maury expresses the opinion¹¹ that the principal cause of forgetfulness of the events of somnambulism consists in the exhaustion of the cerebral elements through the intensity of the excitement to which they are subjected during the paroxysm. Doubtless this in certain cases may contribute to the loss of memory, but it should be remembered that the excitement may be relative rather than absolute. Certain elements wake while others are asleep, and the waking cells may be aroused to a degree far in excess of what is usual during the sleep of the brain without attaining to the level of their diurnal activity. The mind, undisturbed by external impressions, gives its attention to the activity of these waking organs, and a dream with all its consequences, somnambulic or otherwise, is the result. In other words, the plane of consciousness, so to speak, is lowered during sleep to the level of these molecular vibrations. But when the whole brain is again awakened after sleep the residual vibrations of those elements which yielded the physical basis of the dream, and which, had they occurred during the waking state, might have persisted with energy sufficient to furnish a groundwork for recollection of the ideas which they had originally suggested, are no longer sufficiently energetic to be felt in consciousness. Recollection of mental states thus generated must necessarily be impossible so long as the mind is dependent upon the brain as its register of events. Sometimes, however, the somnambulist, who while awake had forgotten all the incidents of his somnambulic experience, can remember in a subsequent paroxysm all that occurred during the preceding attack. Facts of this kind have been observed in the waking life of certain hysterical persons,¹² but the apparent interruptions of their personality attach to the waking state, while in ordinary somnambulism it is only in sleep that the alternations of memory and forgetfulness occur. A similar recollection of previous visions is sometimes experienced in dreams, showing the close relation that subsists between the dreams of sleep and of somnambulism. The bond of association between these events thus isolated in time must be sought in a renewal of like conditions of the brain during the successive periods of somnambulic exaltation. We must suppose that the molecules which were in a state of functional excitement during the first paroxysm are again aroused in like manner after a period of waking quiescence. If, during sleep, their movements, though of an exalted character, have only just sufficed to arouse consciousness in the form of a dream, it would not be probable that during the phase of comparative inactivity which supervenes when the whole brain is awake their residual motion could disturb the sphere of consciousness. Hence the time occupied by their somnambulic vigor must remain a blank in memory during the waking state. But when the original state of exaltation has been reproduced by a second period of disorder, if the same molecular movements be in any way renewed, the conditions of memory are fulfilled; consciousness is once more aroused as before, and the patient remembers the dream or the events of the previous attack.

¹¹ Le Sommeil et les Rêves, p. 226.

¹² Annales Medico-psychologiques, 5e Série, t. xvi. p. 5, 1876.

Artificial Somnambulism, or Hypnotism.

The phenomena which have now been passed in review are of apparently spontaneous origin during the ordinary period of sleep. But from the remotest antiquity it has been known that certain persons may be thrown into an artificial sleep which closely resembles the condition of the somnambulist. During the persistence of this state certain portions of the nervous system become utterly insensible to external impressions, while other portions acquire an exalted degree of sensibility. The subject of the experiment can then by special methods be placed in such relations with other waking individuals that his surviving sensations, mental processes, and physical actions shall be no longer regulated by his own volition, but by the will of another. Such susceptibility is not common to all persons. About 20 per cent. of the ordinary population is, by some observers, considered capable of experiencing this condition. Heidenhain,¹³ experimenting upon a class of medical students, found only one in twelve who was thus susceptible. Charcot, whose field of observation covers the inmates of the Salpêtrière Hospital, finds the best exemplars of the hypnotic state among the hystero-epileptic females in that asylum. To these experimenters we are largely indebted for the most extended scientific observation of the phenomena of hypnotism, giving precision and publicity to the knowledge of facts which, though equally well known within a narrow circle of investigation¹⁴ during the earlier decades of the present century, have been compelled to await the development of cerebral physiology before their full significance could become apparent to the mass of the medical profession.

¹³ Animal Magnetism: Physiological Observations, by Rudolph Heidenhain.

¹⁴ Braid, Neuro-hypnology considered in Relation with Animal Magnetism, London, 1843.

The antecedent condition most favorable to the production of the hypnotic state is a highly unstable constitution of the nervous system. For this reason the larger number of qualified subjects is furnished by the female sex, especially by those who possess the hysterical temperament. Frequent repetition of hypnotic exercises renders the subject still more susceptible. Heidenhain was at first inclined to believe that such experiences were not prejudicial to the health of the subject, but the observation of Harting in the University of Utrecht, and of Milne-Edwards in Paris,¹⁵ have demonstrated danger to the health of animals subjected to similar experiments. It is easy to discover, in the various clinical narratives published by Charcot and his pupils,¹⁶ evidence that hysterical patients often manifest considerable exhaustion after hypnotic exhibitions; consequently, it cannot be admitted that the practice is devoid of risk to the health of the individual.

¹⁵ Lancet, July 29, 1882, p. 164.

¹⁶ Paul Richer, L'hystéro-Epilepsie, Paris, 1881; Le Progrès médical, 1881-82.

Numerous methods of inducing the hypnotic state have been employed by different experimenters. The greater number consist in modifications of the sensory impulses derived from the periphery of the body. Gentle pressure upon the closed eyelids; convergence of the axes of the eyeballs upon some object nearer than the proper focal distance of the eyes; fatigue of the retina by gazing upon any brilliant or luminous object; monotonous excitation or sudden surprise of the auditory nerve; various impressions through gentle friction or pressure upon different regions of the body,—all these are capable of inducing hypnotic sleep. An appeal to the imagination, or even the mere attempt to abnegate the possibility of vigorous thought by confining the attention to the most trivial of things, sometimes suffices to produce the desired phenomenon. Thus, Heidenhain put one of his students to sleep at a distance by merely informing him beforehand that at a certain hour he would hypnotize him in his absence. The state of ecstatic meditation into which the monks of Mount Athos plunged themselves by the practice of omphaloscopy affords an illustration of the hypnotic effects of concentrated attention.

The duration of hypnotic sleep is exceedingly variable, but if left to himself the patient usually wakes spontaneously, without recollection of anything that has happened. If it be desirable to awaken him before the natural termination of the paroxysm, consciousness can be restored by almost any sudden and energetic appeal to the senses, such as an electric shock, a sudden illumination of the eye with vivid light, or a sharp puff of air upon the face.

According to Charcot,¹⁷ three principal types may be remarked among the hysterical subjects upon whom he experimented: (1) the cataleptic, (2) the lethargic, and (3) the somnambulic. Of these, the first may be developed primarily by any abrupt and powerful impression upon an organ of sense, as a bright light or a loud noise (gong). Fixing the eyes upon some object may produce the same result. Dumontpallier, for example, has reported the case of a young woman¹⁸ who accidentally hypnotized herself by gazing at her own image in the mirror before which she was dressing her hair. The cataleptic state may also be secondarily induced by merely opening the eyes of a patient in whom a condition of hypnotic lethargy has been previously developed. If only one eye is thus opened, the corresponding side of the body alone becomes cataleptic. Closing the eyes causes the disappearance of this symptom, with complete restoration of the purely lethargic state. During the cataleptic condition the several tendinous reflexes disappear, neuro-muscular hyperexcitability ceases; the skin becomes insensible, but the special senses, particularly those of sight and hearing, maintain a partial activity. In this state the senses may become avenues of suggestion for the production of muscular movements, but if left to themselves the limbs remain motionless.

¹⁷ Le Progrès médical, Feb. 18, 1882, p. 124.

¹⁸ Ibid., March 25, 1882, p. 223.

The lethargic state may be induced by simply closing the eyes of the patient or by causing him to fix his gaze upon some definite object. The paroxysm begins with a deep inspiration causing a peculiar laryngeal sound, followed by the appearance of a little foam on the lips. The eyelids are either wholly or partially closed, and are in a state of continual tremulous motion. The eyeballs are generally turned upward and inward. The muscles are completely relaxed. The tendinous reflexes are exaggerated; pressure over a muscle or upon a nerve arouses a peculiar contraction of synergic muscles and of groups of muscles which are supplied by the excited nerve-trunk. The facial muscles, however, do not thus become contractured: they merely contract during the application of the stimulus. If the lethargic patient be rendered cataleptic by opening the eyes, these contractions persist even after awaking, and they can only be dispelled by renewing the lethargic state before resorting to pressure upon the antagonistic muscles—a process by which the contractures peculiar to this species of lethargy may always be annulled. By the approach of a magnet to a contractured limb the phenomenon may be completely transferred to the corresponding muscles upon the opposite side of the body. If upon a limb of a lethargic patient who has been rendered cataleptic by opening the eyes an Esmarch's band be applied, pressure over the bloodless muscles excites no contracture until the band is removed. A contracture is then developed, and it may even be transferred to the opposite limb by the approach of a magnet. To this phenomenon has been applied the term latent contracture.

The extraordinary muscular excitability manifested by these hysterical hypnotics is further illustrated by an observation recorded by Dumontpallier.¹⁹ If one end of a caoutchouc tube one centimeter in diameter and five or six meters in length be applied over a muscle in the leg, and if the other end be in like manner connected with a watch, every movement of the second hand will be followed by a slight contraction in the muscle. The same result follows connection with the wire of a telephone, and if a microphone be introduced into the circuit the incidence of a ray of artificial light upon the instrument, or even its glancing reflection from the eye, will arouse a responsive muscular contraction. Charcot has sometimes observed muscular contractions upon the opposite side of the body when a mild galvanic current was applied to the parietal surface of the head. During the manifestation of muscular hyperexcitability there is complete analgesia, but the senses of sight and hearing seem to preserve some degree of activity. The patient, however, does not manifest any susceptibility to influence by suggestion.

¹⁹ Ibid., Jan. 14, 1882, p. 25.

The somnambulic state may be directly induced by fixed attention with the eyes, by feeble and monotonous excitation of the senses, and by various other methods of an analogous character. This forms the most common variety of the hypnotic condition. It may very easily supervene during either the lethargic or the cataleptic state as a consequence of pressure or gentle friction upon the top of the head. Thus, Heidenhain caused muscular paralysis by rubbing the scalp. Unilateral friction of the same surface produced paralysis of the opposite side of the body without notable affection of consciousness. The eye and the eyelids behave as in the lethargic state. The patient seems asleep, but there is less muscular relaxation than in hypnotic lethargy. There is no exaggeration of the tendinous reflexes, and muscular hyperexcitability is absent. But by lightly touching or breathing upon the surface of a limb its muscles may be thrown into a condition of rigidity which differs from the contracture of the lethargic state in the fact that it does not yield to excitation of the antagonistic muscles, though yielding readily to a sudden repetition of the same form of excitement by which it was originally produced. From the immobility of the cataleptic state it also differs by a greater degree of resistance to passive motion. Though analgesia may be perfectly developed in this state, there is generally an exalted condition of certain forms of cutaneous sensibility and of the muscular sense. Strange perversions of other special senses are sometimes remarked. Cohn²⁰ discovered that a patient who was naturally color-blind “when unilaterally hypnotized was able to distinguish colors which were otherwise undistinguishable.” Conversely, when the cataleptic state is induced the eye becomes incapable of discerning colors. Spasm of accommodation is also present, and is one of the earliest demonstrable symptoms of the hypnotic condition.

²⁰ Brain, vol. iii. p. 394.

These remarkable exaggerations and perversions of special sensibility have been the cause of much scepticism on the one hand regarding the verity of the phenomena of hypnotism, and of much credulity on the other, extending even to a belief in the existence of supernatural and miraculous gifts. But when the fact is once comprehended that in this capacity for uncommon feats of vision, hearing, touch, etc. we observe merely the exaggeration of a process which occurs in every act of attention, the miraculous semblance of the phenomena disappears. Attention implies an increase of activity in certain portions of the brain, with diminution of the function in the remainder of the organ. In the wild excitement of a cavalry charge the soldier feels not the sabre cut which will fill his consciousness with pain so soon as his attention is released from the fetters imposed by the more engrossing events of the combat. So in the somnambulic sleep those parts of the brain which remain awake perform their functions with a vigor that is enhanced by a concentration of cerebral energy in certain restricted portions of an organ that, by reason of its naturally excessive instability, had been previously fitted for the liberation of an inordinate amount of molecular motion. Hence the slightest suggestion of sense may suffice for the most extraordinary perception. Such persons see through their eyelids and hear at a surprising distance. The memory of past events, the recollection of long-forgotten words and thoughts, supplies in this state an abundance of materials out of which an exalted imagination may construct the most astonishing scenes. By this method of combination are produced those remarkable oratorical utterances which by the ignorant have been so widely attributed to the supervision of guiding spirits from another world. In this condition the essential characteristics of the mind of the so-called medium become the real guides of his mental processes. Hence the infinite variety and contrariety of the utterances of such declaimers.

Among other consequences of this exalted susceptibility of the waking portions of the brain may be noticed the effect of suggestions by others upon the mind of the somnambulist. Numerous examples scattered through the literature of the subject²¹ illustrate the manner in which the course of our ordinary dreams may be thus directed. The hypnotic dream is far more easily modified.²² The simplest manifestations of such influence are exhibited in movements in obedience to the command of the hypnotizer. Next in rank are those more complicated actions that are effected by excitement of the imitative faculties of the subject. Every suggested movement that can be in any way perceived by the patient will be at once reproduced. Various emotions and passions may thus be aroused by simply placing the sleeper in the appropriately suggestive attitudes. Under the influence of a pregnant idea intruded upon the mind of the patient the subsequent association of ideas will suffice for the evolution of a complicated series of hallucinations, as in the case of a young woman, who on being directed to put out her tongue immediately began to feel sensations of uneasiness in her stomach, followed by nausea and attempts at vomiting, accompanied by the impression of being on shipboard. In the lowest grades of the hypnotic state consciousness may remain, and the subsequent recollection of the events of the paroxysm may be quite persistent. In such cases illusions that were produced by suggestions from other minds generally survive in memory and become the causes of serious delusion. Witness the manner in which susceptible individuals, partially hypnotized in a so-called spiritual circle, believe in the reality of the illusions which have occupied their senses during a séance.

²¹ Carpenter's Physiology, 8th ed., p. 765; Le Sommeil et les Rêves, par L.-F. Alfred Maury, 4th ed., p. 153 et seq.

²² Loc. cit., p. 357.

A higher degree of insensibility to ordinary impressions is necessary to the production of the phenomena of passive obedience and of automatic imitation. It is probable that the degree of sensory hyperæsthesia which enables certain hypnotic patients to read the thoughts of others belongs rather to the first than to the last of these classes. This capacity is usually associated with preservation of consciousness and memory, and is, essentially, a mere exaggeration of that power which all possess in greater or less degree. Numerous well-authenticated examples of a surprising manifestation of this faculty have been recorded, so that the possibility of its existence no longer admits of doubt.²³ In all cases it has been remarked that the hypnotic mediums can only respond correctly to questions for which the true answer is present in the mind of the questioner. For all other interrogations the replies are delivered purely under the influence of random suggestion. In certain of these cases the pathway of communication lies through actual physical contact, as in ordinary mind-reading, where the insensible molecular oscillations of the muscular elements of one individual serve to guide the movements of another. But more frequently the transmission of ideas is effected through the eyes. With these organs the table-rapper or the planchette-writer reads the unspoken words of the questioner in a manner very like, yet vastly more deliberate than, that by which deaf-mutes now learn to interpret the movements of the lips of persons with whom they converse. This fact is well illustrated by the experience of Maury²⁴ in an interview with a celebrated table-rapper, who without the slightest hesitation made known to him the age, name, and date of death of a brother whom he had lost. She also gave the same information regarding his father, and related the names of other persons upon whom he had fixed his attention. But if he turned away his face or concealed his eyes, so that the woman could no longer watch their expression, her responses ceased to be of any value.

²³ Luther V. Bell, Two Dissertations on what are termed the Spiritual Phenomena, read at the meetings of the Association of Medical Superintendents of American Insane Hospitals at Washington and Boston in 1854 and 1855.

²⁴ Le Sommeil et les Rêves, 4th ed., p. 361.

In these partial developments of the hypnotic state it is worthy of note that the phenomena of sleep are so few and so comparatively insignificant that they are usually overlooked. Hence the veil of mystery which has so often obscured the interpretation of such cases. Careful observation, however, will always detect some characteristic departure from the normal standard—some loss of balance between the different parts of the nervous system—by means of which the true relations of each example may be determined.

TREATMENT.—A large proportion of the phenomena of somnambulism and hypnotism depend rather upon an originally irritable organization than upon a specially diseased condition of the nervous system. Their treatment, therefore, frequently resolves itself into the management of hysteria or of cerebrasthenia. But if the manifestations of somnambulism develop for the first time in a person advanced in years, who has previously enjoyed good health and a sound mind, it should be regarded as an omen of grave import, signifying the imminence of organic cerebral disease. Though the meaning of such incidents is less sinister in early life, they reveal an ill-balanced state of the nervous system and an imperfect process of nutrition in the growing body. Such children are the frequent victims of night-terrors, the form of disorder most commonly evolved by their somnambulistic proclivities. The treatment of night-terrors should therefore be chiefly directed to the invigoration of the general health of the patient. Indigestion and malnutrition are among the most prominent antecedents, and they should constitute the principal objects of therapeutical attention. Constipation is usually present. This may be relieved by the use of compound rhubarb powder or any other gently stimulating laxative. Digestion should be aided with pepsin as soon as the catarrhal condition of the alimentary canal, so uniformly present, has been measurably improved. Cod-liver oil or its substitutes should be administered for a long period of time. If the nocturnal paroxysms be frequently renewed, it may be well to employ the bromides, either with or without chloral hydrate; but as a general rule it is better to rely upon hygienic and restorative treatment, rather than upon any form of merely hypnotic medication.

INSOMNIA.

The departures from the course of natural sleep which have been thus considered are not so much the direct consequence of acute disease as the result of structural deviation from the normal type of the nervous system. We must now briefly review the strictly pathological modifications to which sleep is liable.

Lithæmic Insomnia.

Among those who indulge freely in the pleasures of the table a form of insomnia is not uncommon. Originating at first in mere overloading of the stomach, and consisting in a direct irritation of the brain through the medium of the intervening nervous apparatus, sleeplessness finally becomes a symptom of more serious mischief. The tissues become charged with nitrogenous waste, and a lithæmic²⁵ or gouty condition is established. Such patients are wakeful, or if they sleep their slumbers are imperfect and unrefreshing.²⁶ Grinding of the teeth,²⁷ noticed by Graves during the sleep of the gouty, is a symptom indicative of a highly irritable condition of important ganglia at the base of the brain. These symptoms are sometimes associated with turgidity of the superficial vessels of the head, indicating imperfect function of the circulatory organs, with a tendency to accumulation of the blood in the venous channels of the body. The sleep of such partially-asphyxiated patients is fitful, irregular, and akin to stupor. Occurring in the subjects of periodical gout, these disturbances of sleep become increasingly serious as the paroxysm is approached, until loss of sleep and the unrefreshing character of such slumber as may be obtained become important factors among the causes of failing health.

²⁵ DaCosta, “Nervous Symptoms of Lithæmia,” Am. Journ. Med. Sci., Oct., 1881.

²⁶ Dyce Duckworth, “Insomnia in Persons of Gouty Disposition,” Brain, July, 1881.

²⁷ Trousseau, Clinical Medicine, Am. ed., vol. iv. p. 362.

For all such patients a proper recognition of the cause of their disorder is essential. This must be corrected by measures appropriate to the treatment of the gouty diathesis. Since the condition of the cerebral tissues is a state of irritation caused by the presence of excrementitious substances, such hypnotic remedies must be selected as will not interfere with the defecation of those tissues. Bromide of potassium, valerian, scutellaria, hyoscyamus, hops, and cannabis indica are useful, together with all that class of drugs which quiet the brain without hindering the process of excretion. Chloral hydrate often produces an excellent result, but care should be taken to prevent its habitual use.

Febrile Insomnia.

Closely related with the sleeplessness of lithæmia are the disturbances of repose which attend the evolution of the various specific fevers. In many cases the condition varies all the way from stupor to delirium. Excessive somnolence, such as often ushers in the fever, is an indication for evacuant treatment. Cerebral excitement calls for remedies like the bromides and chloral hydrate, which do not interfere with elimination. If pain, like headache or backache, be a symptom demanding attention, the addition of morphia in small doses forms a valuable reinforcement for the hypnotic mixture; but, as a general rule, opiates should be used with a sparing hand. The various resources of hydrotherapy are often invaluable when wakefulness results from the cutaneous irritability of the eruptive fevers. During the later stages of a protracted illness the occurrence of insomnia should direct attention to the nutrition of the patient. Wakefulness is then the symptom of an irritable weakness of the brain, demanding remedies which delay the process of disassimilation. The failing power of the heart requires attention, and diffusible nutriment must be given to convey the elements needful for restoration of the exhausted brain. These indications are most perfectly answered by the associated administration of opiates with alcohol, milk, and beef-juice in small and frequent doses.

Insomnia from Exhaustion.

Cerebral exhaustion is a not uncommon cause of wakefulness in cases uncomplicated with fever. It is usually the result of chronic conditions of ill-health and depression, such as are often encountered as the result of various cachexias or of dyspepsia, with or without the abuse of alcohol, tea, coffee, or tobacco. Overwork, debilitating discharges, pregnancy, parturition, mental anxiety, depressing emotions, chronic heart disease, and incipient insanity are fruitful causes of the exhaustion which produces this most distressing form of insomnia. In such cases the cessation of healthy nutrition leads to a condition of excessive instability in the cerebral tissues. The oxygen which they receive from the blood is not stored with any degree of permanence, but tends to pass directly into stable combinations with the oxidizable elements of the brain. Consciousness is thus continually aroused. The state of such a patient presents a very close analogy to the condition of the victim of diabetes whose liver refuses to retain its glycogen. The inordinate discharge of sugar into the blood not only exhausts the tissues of the liver, but also excites other organs—notably the kidneys—to excessive and unwholesome activity. In somewhat similar fashion, the failure of the brain to assimilate and to retain oxygen leads to an abnormal intramolecular oxidation, which excites an excessive and unwholesome activity on the part of the Ego in another region—namely, in the field of consciousness. Such wakefulness might justly be termed a psychical diabetes.

This variety of insomnia has frequently been ascribed to cerebral anæmia occurring as a part of a general spanæmia. But this universal impoverishment of the blood, though a sufficient cause of the morbid instability, the irritable weakness, of the cortical tissues, does not necessarily imply a comparatively bloodless condition of the brain. Unequal circulation and local hyperæmia in different organs of the body are no unusual consequences of the anæmic state. Slight disturbances suffice to arouse the brain of such a patient. The vaso-motor apparatus shares in the general irritability, permitting blood to inundate the cortical substance almost without provocation. The unstable protoplasm is only imperfectly renovated, usually at the expense of the other tissues of the body. The weary patient, busying himself with an unwilling review of the events of the day, tosses long upon his couch before he can secure the approach of “tired Nature's sweet restorer, balmy sleep.” When at length he yields, his slumbers are brief, and the latter part of the night is but a repetition of the earlier vigil.

Such patients need a very radical course of general treatment. A complete change of habits should be effected. A long vacation in the country, or, best of all, a protracted voyage in a sailing vessel, is desirable. Hot foot-baths, with cold affusion upon the head, and warm sponge-baths, or even the full bath in tepid water, at bedtime, are of great service as means of tranquillizing the nervous system. The indications for medicinal treatment, besides attention to the predisposing cachexia, are twofold—to calm and to nourish the enfeebled nervous substance. Opiates calm, but do not nourish—they hinder the process of nutrition; hence the sufferer wakes unrefreshed by the sleep which they procure, and is soon in a condition worse than ever. The same objection lies against the continuous use of the bromides. But alcohol and its hypnotic derivatives (chloral, paraldehyde, etc.) not only calm the excitable brain, but they also furnish to the tissues a certain amount of diffusible nutriment which suffices to steady the brain until a change of occupation, with rest and wholesome food, can produce a complete restoration of its normal stability. To this effect of alcohol must be ascribed its value as an hypnotic in the wakefulness of old people who cannot sleep without a preliminary nightcap. A moderate draught of hot toddy in such cases serves to arouse the feeble heart and to equalize the circulation by the production of a moderate degree of general vascular dilatation. The sugar and water afford an easily assimilated food, while the alcohol benumbs the cortical protoplasm to a degree which favors the cessation of conscious perception. If administered in excessive doses, it is not sleep but anæsthetic intoxication which follows. If this condition be unduly repeated, the phenomena of chronic alcoholism supervene, with all the horrible forms of insomnia that accompany cerebral starvation and delirium tremens. Non-alcoholic nerve-stimulants and tonics, with careful administration of easily-digested food, are then more than ever needed to overcome the neurasthenic wakefulness.

Insomnia from Active Cerebral Congestion.

Still another form of sleeplessness is often experienced as a result of actual inflammation in some portion of the body, either involving the intracranial contents directly or reacting upon the brain through the medium of its circulation. In such cases many of the symptoms of acute inflammation are present. The head aches, the temples throb, the face and eyes are suffused with blood, the temperature is considerably increased. The senses become exalted, ideas pursue a tumultuous course, there may be actual delirium. These disturbances are due to an active hyperæmia of the brain. The substance of the cortex becomes hyperexcitable, and the ordinary incitements of sense produce an exaggerated effect in consciousness. The patient does not sleep, and he feels no need of sleep, because the nutrition of the brain is sustained at the expense of the remainder of the wasting body. The most speedy and effectual relief in such cases is obtained through a diminution of the current of blood in the brain. Moderate compression of the carotid arteries has been proposed as theoretically useful. Sedatives, like aconite, conium, digitalis, veratrum viride, ipecacuanha, and tartar emetic are useful, either alone if pain be absent or combined with opiates if the patient is suffering. Dover's powder or tartar emetic and morphia in small doses was formerly in general use. If there be a disposition to nausea the substitution of aconite for antimony is of great value. A combination of morphia, bromide of potassium, and chloral hydrate often gives excellent results. Paraldehyde may be preferable to chloral by reason of its more thoroughly sedative effect. Derivative measures—mercurial cathartics, cupping, leeching, or even general bleeding—may become necessary in certain cases. After the acute stage is passed blisters behind the ears should be employed. In the sleeplessness of acute mania Newington²⁸ has used mustard baths with great satisfaction.

²⁸ Brain, vol. i. p. 126.

Coma.

Turning now to the other extreme, we find a class of cases in which the disorder consists not in wakefulness, but in an excess of sleep. Excluding those exceptional cases in which healthy individuals, as a consequence of inordinate physical exertion, have slept for many hours beyond their ordinary limit, every extraordinary manifestation of sleep-like unconsciousness must partake of the nature of coma. Between natural sleep and this condition may be placed the distinction that the one is always the effect of natural physiological processes, while the other is always the result of injury, of disease, or of some form of intoxication. Comatose unconsciousness may be the result of cerebral compression caused by traumatic impact or by the presence of inflammatory exudations. Intracranial tumors, embolisms, thrombi, degeneration of tissue, diseases of the arteries of the brain—in short, every morbid change of which the liquids and the solids within the cranium are capable—may become the causes of coma. So also the blood and lymph, contaminated with the products of internal disintegration, may benumb the brain with comatose sleep. Again, the tissues of the brain may be overwhelmed with poisons introduced from without the body, and thus a condition of coma may result. Few diseases, therefore, exist without the possibility of coma as one of their consequences—a coma which, however, must not be confounded with the genuine sleep which sometimes occupies the larger part of certain stages of convalescence from acute illness. During such convalescence there is a reversion to the infantile type of nutrition, with all its need of prolonged and frequent periods of repose. Like normal sleep, the comatose condition admits of considerable variation of intensity. The patient may sometimes be partially roused, as from the coma of alcoholic intoxication, and he may finally recover complete consciousness, but very often the reverse is the fact. The coma deepens into paralysis, and death terminates the scene without the slightest manifestation of sensibility or intelligence.

Sleeping Dropsy (Maladie du Sommeil).

A singular disorder, characterized by daily paroxysms of somnolence, tending to become more and more continuous and profound until merged in fatal coma, is encountered among the negro inhabitants of the Atlantic coast of tropical Africa. Similar cases have been occasionally reported in other regions of the world, but it is among the Africans that they have been principally observed. For our knowledge of this disease we are chiefly indebted to the writings of Clark,²⁹ an English surgeon residing at Sierra Leone, and of Guérin,³⁰ a surgeon in the French navy, who enjoyed unusual opportunities for its study among the laborers recently brought from Africa to the island of Martinique. According to these observers, the onset of the malady is gradual, commencing with a slight frontal headache. Very soon a disposition to sleep after meals is remarked. This becomes increasingly urgent, and the paroxysms of sleep are prolonged, until at length the patient becomes continually soperose. The wakeful intervals are marked by a sluggish state of the intellectual faculties. The pulse is not accelerated, but remains full and soft. The veins of the sclerotic become turgid and the eyeball seems unusually prominent. The temperature does not increase, but rather tends to diminish its figure. The skin becomes dry and moderately cool. The tongue continues moist, and is covered with a white fur. The contents of the bowels and of the bladder are regularly voided, and the appetite persists with considerable vigor. Finally, the patient becomes completely comatose and dies quietly. Sometimes, however, the evolution of the disease is less tranquil. Epileptiform convulsions, followed by progressively deepening paroxysms of coma, interrupt its course, until a continuous muscular tremor marks the closing period. At the same time the pulse grows weaker and more frequent, until its movements cease in death. Recovery is almost unknown, though the duration of the disease often varies from three months to a year or longer. Examination of the body after death has thus far yielded very negative results: the sinuses and larger vessels of the brain are engorged with blood, but no evidence of inflammation is anywhere apparent. The other organs present no pathological alterations whatever. These observations seem to indicate that the disease originates in some form of general blood-poisoning rather than in any local inflammation or degeneration, and Clark has called attention to an enlargement of the cervical glands as a feature of the malady. According to G. H. Bachelder,³¹ the native physicians cure the disease by extirpation of the affected glands. He has also observed an initial lesion in the nasal mucous membrane. If this be confirmed, the malady will take its place among the forms of coma produced by septic poisoning.