Volume 3 — DISEASES OF THE BLOOD, AND OF THE HÆMATOPOIETIC SYSTEM. (continued 5)

B. Combination with cor biloculare.—Here we have a heart consisting of two cavities—one auricle and one ventricle—where no partitioning has taken effect. The defect results from the failure of the septum ventriculorum to grow; and with this, as in the former division, comes also a more or less complete failure of the septum trunci art. comm.

C. Combination with single ventricle and divided auricles (cor triloculare biatriatum).—In the cases of single ventricle with more or less complete division of the auricles the pulmonary artery generally shows narrowing to a greater or less degree; it may still be pervious, although its orifice is closed, or it may be throughout entirely obliterated. The valves may be entirely wanting. The duration of life is very short, though in a very few with effective compensatory changes it may be prolonged very considerably.

D. Combination with divided ventricle and a single auricle (cor triloculare biventriculare).—In strictness, this defect is nothing more than an open foramen ovale with some deficiency of the pulmonary artery; but, in reality, the heart is much more malformed. The whole septum atriorum is wanting; the superior or descending vena cava is doubled—one entering the left part of the common auricle, the other opening more to the right. The ventricular septum shows a greater or less defection, the pulmonary artery is narrowed, and the aorta arises from both ventricles or wholly from the right one.

E. Combination with special anomalies in the position of both the great arterial trunks.—Here come a variety of anomalies in the arrangement of the aorta and the pulmonary artery in relation to their respective ventricles and to themselves.

a. In transposition of the great arteries, the aorta arising from the right ventricle and the pulmonary artery from the left cavity, either there comes a general transposition of all the viscera or the heart alone is reversed. Very rarely in transposition of the vessels the septum ventriculorum is closed, commonly open, and although the size of the vessels may be normal, usually their relation and position continue reversed throughout their course. In cases where the pulmonary artery is narrowed the duration of life is short. b. The pulmonary artery may arise from the left ventricle and the aorta from both ventricles; or, c, the aorta may come wholly from the right ventricle, and the pulmonary artery from both cavities; the latter vessel may be narrowed or show its normal width or even be considerably dilated. d. Both the great vessels may arise from the left ventricle, very much dilated, with the aorta in front of the pulmonary artery and the latter narrowed. e. The relation of the great arteries may be found reversed—i.e. the aorta in front and the pulmonary artery behind, and the aorta spring from both ventricles and the pulmonary from the right alone.

F. Combination with primary defects of other valvular orifices of the heart.

a. The tricuspid valve may be quite rudimentary, producing by the regurgitation thus allowed, especially when combined with pulmonary stenosis, great dilatation of the right auricle. When the pulmonary artery is narrowed the septum ventriculorum remains open; the aorta carries the blood, distributing it to the lungs by an open ductus arteriosus Botalli or a collateral circulation. The collateral circulation is less developed the greater the width of the pulmonary artery. The foramen ovale may close in such a case, but when it remains open the relief to the over-distended right auricle is very great.

b. Many cases of congenital stenosis and atresia of the right auriculo-ventricular orifice are reported in which the condition of the pulmonary artery is not described. In fact, it is a difficult matter to determine if the auriculo-ventricular narrowing is a primary one. Its defective size may be merely, as it were, a rudimentary condition, a failure to enlarge through disuse. When the pulmonary orifice is closed and the right ventricular cavity remains small, the tricuspid orifice is naturally small in size. There are, however, undoubted cases of tricuspid narrowing with or without stenosis of the pulmonary artery; the defect consists in a primary contraction of the fibrous ring or in the union by partial adhesions of the leaflets.

Malformations affecting primarily the Left Side of the Heart.

Primary defects of the systemic side of the heart are, for the reasons already given, very much more rarely seen than those of the pulmonary heart. In such cases the aortic conus and its orifice are found more frequently affected than the mitral orifice; both of these orifices, however, may be congenitally altered without foetal malformations at other parts of the heart being present; such cases are on record, though only sparsely scattered through the literature of cardiac diseases. Dilg⁸ has recently made an important addition to this subject. He proposes a classification on a new basis for all forms of cardiac malformation; to these classes he makes conform the malformations of the left side of the heart. In the first class he places all cases dependent on an inflammatory process occurring in the foetal heart after its normal development is completed; in the second, those cases of malformation in which the deviation from the normal consists in defects of formation; in the third, those which present a combination of endo-myocarditis with defective development.

⁸ Virch. Arch., Bd. xci., S. 193–259, 1883: "Ein Beitrag zur Kenntniss seltener Herzanomalien in Anschluss an einem Fall von angeborner linksseitiger Conusstenose."

Among the many cases of malformation of the heart which he presents there are reports of 15 cases of stenosis of the conus, which are to be divided into two categories, in accordance with his classification. In the first group, in 7 cases the stenosis is due to an inflammatory process, and is conditioned by the results of the endo-myocarditis localized in the aortic conus. These cases must have originated at a late period of foetal life, and they correspond closely to the conditions arising in the adult organs from similar processes. In all the specimens the mitral orifice was involved, and contributed a share in the production of the conus stenosis; in all the cases the aortic valves also had suffered inflammatory changes. Here Dilg also speaks of a band-like hypertrophy of muscular fibres, marking the outlines of the aortic conus, similar to the condition described by Peacock in the right ventricle; in this condition there was no evidence of endocarditis, and the condition may have been due to cadaveric rigidity. The left ventricle presented varying conditions according to the state of the aortic and mitral valves; in some cases there was concentric hypertrophy, or, more strictly speaking, narrowing or shrivelling of the cavity with hypertrophied walls; in others dilatation existed. The other cavities of the heart were influenced by the competency of the mitral orifice, but almost always showed considerable hypertrophy and dilatation. The valvular apparatus of the right heart was not free from evidences of old inflammation, but this condition was not very marked. The ages of the reported cases reached from thirty to seventy-five years.

In the second group there are eight cases in which the defective condition of the aortic conus caused malformation of other parts of the heart. Here the conus stenosis occurred at an early period of foetal development, before the permanent structures of the heart were fully formed. The conus stenosis is to be considered as primary, the other defects as secondary. As we have already seen, the left side of the heart is much less liable to deforming causes, and when such do occur the secondary defects are less conspicuous. Thus, in only four of these cases were there such malformations of other parts of the heart as openings in the septa of the ventricles or auricles, patency of the ductus arteriosus Botalli. The defects consist more usually in what were formerly called excesses of development, such as the formation of bands below the aortic orifice; or of deficiencies of development, such as only two aortic valves. These conditions are very doubtfully due to formative excesses or deficiencies, but rather to intense inflammatory processes or other morbid conditions which have resulted in the formation of excessive cicatrices or the removal of normal parts.

Another division of cases shows narrowing of the aortic trunk itself. This condition is probably always a true defect of development; so far as these cases, collected by Dilg, show, it is unquestionably so. In narrowing or closure of the pulmonary artery trunk it is found that in some instances this condition was dependent on an endarteritis resulting in a partial occlusion of the lumen of the vessel; here, however, the aortic trunk furnishes no evidences of such a process. It must therefore be due to an unequal division of the truncus arteriosus communis. The cause and the mechanism of this unequal division of the common trunk, resulting in a reduction of the size of the aorta, are probably similar to what Rokitansky indicated for the reduction in the size of the pulmonary artery trunk.

In the specimens of aortic narrowing (no cases of complete closure are reported) from this cause and mechanism the pulmonary artery has been found unusually wide, but this condition of the pulmonary trunk is not very conspicuous, and does not necessarily result from the narrowed state of the aorta. The compensatory or secondary defect of open septum ventriculorum, or even of the auricular septum, is, in these cases, neither invariable nor necessary to a proper maintenance of the foetal or adult circulation. In fact, the open ventricular septum is rare; the condition of the auricular septum is, in the reports, often not stated. The left ventricular walls commonly show a preponderance of hypertrophy over dilatation of this cavity, but in some cases the distension of the cavity is marked.

SYMPTOMS.—The most striking symptom which occurs in malformation of the heart is the cyanosis, but the appearance of this peculiar symptom may be postponed until some time, even a long period, after birth. In the newly-born infant presenting a blue color the diagnosis rests between the not infrequent temporary failure of respiration from many causes and a defective development of the circulatory organs. In most cases the doubt is promptly solved by the voluntary or artificial efforts of breathing, whereby the cyanosis disappears. If the dark hue persists after the respiratory movements have been developed, the cyanosis may be found to depend either on cardiac malformation or an imperfect expansion of the lungs (atelectasis). The distinction between these two conditions can usually be made by a study of the respiratory movements, by the state of the heart's action and of the pulse, aided sometimes by an inspection of the outlines of the chest. In cardiac malformation respiration seems to be well performed and full, though often hurried or labored; in atelectasis this function is often found characteristically altered by being short, high, and imperfect, with imperfect distension; the ribs, instead of moving upward and outward, fall toward the median line, and the chest fails to expand transversely. In malformation the heart's action and the pulse are rapid, and a murmur can often be heard. The thoracic outline may deviate from the usual antero-posterior flattening by the sternum being prominent in cases where the heart, instead of its usual position to the left, is placed more centrally, as comes in certain defects of development. Both of these conditions may be present, and then the symptoms are mixed in character.

Cases of atelectasis, sufficiently marked to give rise to persistent cyanosis, if not relieved too frequently show a pretty rapid increase of color, becoming deeply livid, with convulsive movement, ending shortly in death. The diagnosis in such cases between a cardiac malformation and a non-expanded lung is almost impossible unless the respiration shows characteristic features. It is probable that the treatment proper for the latter would aggravate the condition of the circulation in malformation. In a majority of cases a post-mortem examination is necessary to determine whether the cyanosis is of cardiac or of pulmonary origin. In the atelectatic condition, if death comes within a few days of birth, the ductus arteriosus Botalli and the foramen ovale may both be found open, especially the latter, their time of normal closure not having arrived; in cases dying at a later period, if the foetal openings are still found patulous, the open state must be considered as dependent on the condition of the lung-tissue, since in malformation of the heart the patulous state of these foetal openings is, as has already been shown, rare as a primary defect, and, except in connection with defects of development resulting in obstruction, which operate at other points of the foetal circulation, is almost never found. In other words, an open foramen or ductus is a secondary defect, dependent, on the one hand, on a primary obstruction of the cardiac ostia, or, on the other hand, it may be on a primary atelectasis or malformation of the lungs.

If the child passes beyond the first weeks of life without exhibiting cyanosis, the subsequent occurrence of the condition becomes almost a pathognomonic symptom of cardiac or vascular malformation, unless it can be shown that the coloration is dependent on some acute disease, especially acquired valvular disease: in this connection collapse of the lung (post-natal atelectasis), too, must be remembered.

It is during the first week of life that cyanosis makes its appearance in the great majority of cases of malformation of the heart, in the proportion of more than two to one of the cases. The coloration, once developed, may remain permanent and of equal intensity until death, but as less than 8 per cent. of infants with malformation die within the first week, and only 36 per cent. within the first year, this symptom usually remits. It may wholly disappear, to return on very slight provocation, such as excitement, or on exertion, on the advent of acute disease, or without apparent cause. Probably about one-fourth of those who die in infancy perish in paroxysms of dyspnoea, another quarter of acute disease, and the remaining half of convulsions; and toward death the cyanosis generally becomes very intense.

If the malformation is not of character or degree to develop cyanosis early in life, the child grows and passes through the usual stage of development, usually, however, feeble, poorly nourished, incapable of common exertion, but often without any special phenomena to attract attention, and the vice of formation is undetected unless by a special examination. There are several other symptoms frequently present in connection with malformation, but not of a pathognomonic character. Dyspnoea, though rarely occurring without cyanosis, may attract attention, and, if frequently brought on by active exercise, increases in violence, to be later accompanied with the cyanosis originally absent. Palpitation is not uncommon, especially in cases of great hypertrophy with dilatation, in hearts struggling to overcome an obstruction; in other cases it is absent or only occurs on exertion in connection with dyspnoea and cyanosis. The degree of animal heat varies greatly, judging by the various opinions expressed by writers. The sensation of patients able to express their feeling is often that of chilliness, and in some cases the surfaces of the body feel cold, although the indications of the thermometer show no great variation from the normal temperature. It is obvious that no very great variation from this standard is compatible with the long duration of life, although a depression may exist during or immediately after paroxysms of dyspnoea or cyanosis. Cough is also frequent, but is probably always due to some acquired pulmonary disease.

The physical signs offer increased facilities for the recognition of defects of development. In the early reported cases there are of course no records of these conditions, and there is therefore a lessened number of instances from which to collate the physical signs. In the early days of life it has been shown wherein the presence of a cardiac murmur may lead to the distinction between malformation and atelectasis. In later periods of life the physical signs cannot be regarded as characteristic. There are no signs by which a malformation can be distinguished accurately from an acquired cardiac disease, so that without the clinical history and a grouping of symptoms the diagnosis cannot be made from the physical examination.

Inspection and palpation of the chest often show the heart to be in an unusual position, placed more centrally under the sternum. It must be remembered that transposition of the heart to the right side is not unfrequently unaccompanied with any malformation of its ostia giving rise to symptoms; and this organ may be even more markedly displaced without being malformed, although under both these conditions irregularities of the principal trunks are usually found.

Percussion frequently shows enlargement of the area of cardiac dulness, but, on the other hand, at the post-mortem examination the heart is often found markedly defective without externally showing variation of its size or shape, or of its position within the thorax; hence in such cases no deviation from the normal will be revealed on percussion or inspection of the chest. It is probable that cardiac murmurs are not always to be detected in cases of even marked defects of development, but when present it is recorded most frequently that a single murmur is heard over the base of the heart, blowing in character and systolic in time. Such a sound is probably produced by the passage of the blood through an abnormal opening between the ventricles or through the foramen ovale. Other murmurs may also be present; if the arterial ostia are defective from narrowing, roughness, or insufficiency of their valvular apparatus, abnormal sounds of different characters, diastolic or systolic in time, may be heard. Too few observations as yet exist for a general diagnostic scheme to be formulated. Auscultation of the intra-uterine heart may in the future become sufficiently accurate to enable us to prognosticate a congenital cardiac malformation or disease; there is one case on record in which a correct diagnosis was made in this way.

The ends of the fingers and toes are frequently described as bulbous. This rounding and retraction of the nails, frequently spoken of as clubbing, does undoubtedly exist in many cases, but the condition cannot be regarded as characteristic of malformation of the heart, since it comes with even more frequency in tubercular disease of the lungs, in chronic pleurisy, and in other chronic pulmonary maladies.

Lebert has recently insisted on the connection between stenosis of the pulmonary artery and tuberculosis, not merely as a coincidence, but as the cause of the development of the tubercles in the lungs. Many others have spoken of this connection, and very many are the cases recorded—perhaps nearly one-quarter of the whole number. In some cases large or small single cheesy masses exist; in others cavities form, and in rare cases a miliary tuberculosis exists, still more rarely affecting other organs than the lungs. In view of the recent dogmas of tuberculosis it is doubtful if many of these authors would at present insist on the connection between malformation of the heart and tuberculosis being other than a coincidence, since it is not apparent why such patients are more likely to be invaded by a bacillus of tuberculosis than other persons, and this organism is known to grow so readily wherever the spores chance to fall.

DURATION OF LIFE.—In connection with certain malformations some indications have already been given in respect to the duration of life in such defects. It is, however, apparent that the degree of the obstruction to an orifice or vessel, and still more the completeness of the secondary compensatory alterations, exert a greater influence than the seat of the malformation on the continuance of life. The occasional slight isolated malformations, such as open septa without obstruction of the orifices, in themselves often entail no symptoms, and, unless combined with acquired valvular disease, exercise no influence on the duration of life; here, however, the prognosis merges entirely into the acquired malady.

Of the other conditions of malformation, narrowing of the aorta and of the aortic conus seems to be, on the whole, compatible with a longer duration of life than any other condition, and these defects cause death in the early days or months in fewer cases than similar obstructions on the right side of the heart. This result apparently comes from the fact that the left ventricle seems to possess unlimited capacity for hypertrophy, and hence is able to overcome the obstruction; when the aortic valves allow of regurgitation the compensation fails and death comes sooner. When the main branches of the aorta are defective or when the descending aorta is derived from the pulmonary artery, the duration of life is much shortened.

In cases of pulmonary narrowing in general it may be stated that the greater the obstruction the shorter the life. This rule is subject to many exceptions; so frequent are the exceptions that the rule is almost valueless for determining the life in any given case. Complete closure of the pulmonary trunk has permitted of the continuance of life for sixteen years, and then ended from an intercurrent acute disease. When the septa are maintained open—when, therefore, the communications between the pulmonic and systemic sides of the heart are free—a greater age is attained than when these openings have become closed. This condition of the pulmonary artery in order to permit of a long duration of life must be coincident with a considerable development of the collateral circulation by which the blood freely enters the lungs for aëration; otherwise the compensation fails very soon.

In transposition of the main trunk relatively to the ventricles, with closure of the septum ventriculorum (very rare), life ends not many weeks after birth; if the septa remain open, which is not common, life may be prolonged for a year or two.

Cyanosis.

There are two views to be found, set in opposition to each other, to account for the peculiar blue coloration of the skin and mucous membranes in cases of malformation of the heart. The first explanation attributes the phenomenon to a general congestion of the venous system, due to the obstruction of the pulmonary artery. This view was proposed by Morgagni in connection with his, the first described, case of malformation of the heart. The other view considers that the intermingling of venous and arterial blood through any channel, but especially by means of abnormal openings in the septa, produces the blue coloration. Numerous writers have defended each of these theories of causation; from most of their observations darkness rather than light has resulted through the attempt to defend one or the other theory exclusively.

Gintrac defended the admixture theory for cyanosis, and his views became so well known that a large majority of persons conformed their belief to his teachings. This author distinguished four varieties of blue coloration: first, that due to some malformation of the heart or great vessels, by which the blood of the right side of the heart enters the systemic arterial circulation; second, likewise due to intermixture of the blood, but produced by conditions developed after birth through the re-establishment of the passages of communication or other changes in the circulation; third, where the coloration appears without direct admixture of the blood, but from organic disease of the heart; fourth, cases without malformation, from a suppression of the menses. Before the time of Gintrac, cyanosis had a very indefinite signification, and the condition was looked upon, and was classed by very many, as one of the cachexiæ, and was often spoken of as a form of icterus. He, however, held that the organic lesions of the heart and great vessels were the necessary conditions of its production, and that the mixture of the red and black blood, and the distribution of the mixed fluid by means of the arteries to all parts of the body, determined its essential character. He showed, too, that all communications between the right and left heart were not followed by cyanosis; the explanation of the absence of the blue color was that from the simultaneous contraction of the auricles and ventricles of the two sides of the heart an equilibrium was produced, and the blood did not deviate from its normal course. This result followed only when the normal exits of the blood were unobstructed. This supposition, as is apparent, is not in accord with the facts. During the filling of the ventricles, before the muscular contraction of the walls occurs, the blood has the opportunity of freely mingling if the opening between the cavities is sufficiently large: that the blood will not thus mingle when the muscular contraction acts remains to be proved. Cases of open septum ventriculorum, as an isolated defect, without obstruction of the great vascular trunks (a rare condition), are not attended with cyanosis: the absence of this symptom, as will be shown later, is readily to be explained on other grounds than those supposed by Gintrac. The normal outlets of the blood are, however, almost always obstructed to a greater or less degree; and here the explanation of the absence of the cyanosis fails. In the delayed appearance of cyanosis Gintrac considered the reason to be that the venous blood differed less from the arterial in the young subject than in those of more advanced age, because, on the one hand, the aëration was more active, and, on the other hand, the deterioration of arterial blood was less marked. In other cases he points to an increase of the obstruction, through inflammatory changes, as the probable reason for the delayed appearance of the blue color; in still other cases it was supposed to be due to a disturbance of the equilibrium of the pulmonary and systemic circulation from an increase in the blood-mass. In cases of unilocular and bilocular hearts, of which the author speaks, his explanation completely fails, for here the admixture of the blood within the heart is very marked; yet such cases have been reported without cyanosis. He further believed that openings in the ventricular septum, as well as between the auricles, were effected after birth as the results of acquired cardiac disease.

Gintrac, in speaking of the causes of cyanosis, says that the condition shows no hereditary tendency; that the pregnancy during which the defective infant is developed is without noticeable phenomena; and that the confinement is normal. It is on some of these points that we are in want of accurate information. It has been pointed out that many congenital defects of the heart result from morbid processes affecting the organ during its developmental stage. These lesions are the same in kind as those which produce cardiac and vascular disease in the adult, and are likewise of a sort capable of communication from the parent to the foetus. Such diseases are found acting oftentimes temporarily in the parent; and if they acted during pregnancy, or even if present only at the time of conception, their results would rationally be expected to be displayed in the foetus. Such diseases as rheumatism and syphilis, which may be regarded as temporarily-acting maladies, would come under this class, and doubtless many others might be added to the list. The work of collecting the histories of pregnancies or the condition of the parents at or before the time of conception would be painfully tedious: such records do not exist at present, and they could be made sufficiently full only in exceptional cases; but their value in determining the causes which operate in the production of defective development of the heart cannot be too highly estimated.

The conclusions stated by Moreton Stillé⁹ seem to be the first which justly cover the ground from a comparison of large numbers of cases of malformation of the heart. The first conclusion by him is that cyanosis may exist without admixture of the blood; by this was meant that no abnormal communication between the right and left sides of the heart, and no channels between the principal vascular trunks, are present. He mentions five cases of cyanosis occurring in which no means of admixture existed. The second conclusion is that there exists no proportion between cyanosis and the degree in which the blood is mixed; for this he cites four cases, some with the aorta arising from the right ventricle, others of hearts with only two cavities and the common trunk undivided, in which the cyanosis was only partial or transient. The third conclusion, the converse of the first, and reinforcing the preceding one, is that complete admixture of the blood may take place without cyanosis. The fourth, that the variation in the extent, depth, and duration of the discoloration is inexplicable by the doctrine of the mixture of the blood.

⁹ "Inaug. Thesis." Amer. Journ. Med. Sci., N. S., vol. viii., 1844.

Having shown that commingling of arterial and venous blood cannot be the cause in itself of cyanosis, Stillé proceeds to the study of the other theory—viz. that it is due to congestion of the general venous system resulting from some obstruction in the right side of the heart or in the pulmonary artery, impeding the passage of the blood through the heart. These structural lesions must fulfil the three following indications: 1st, that they shall be sufficient in degree to account for the symptom; 2d, that they be present in every case of cyanosis, or in their place some other cause acting on similar principles; 3d, that they shall never exist without cyanosis or without a satisfactory explanation of the exceptional occurrence. He holds that contraction of the pulmonary artery is to be taken as the type of all the lesions that may produce cyanosis, and that this type fulfils the indications given above.

Most writers since Stillé have coincided with him, or have regarded cyanosis as partly due to venous congestion and partly to commingling of arterial and venous blood. Some writers, however, have pointed to the abnormal communications between the right and left side of the heart, and asked why, if admixture of the venous and arterial blood is not the cause of cyanosis, should the admixture through such openings be found in such a large proportion of cases. Such writers have failed to distinguish between the primary and secondary defects of development. They have failed to see that the pulmonary obstruction which prevents the blood during extra-uterine life from passing to the lungs for aëration, and consequently produced the cyanosis, prevented the closure of the ventricular septum during intra-uterine life, or of the auricular septum within a few days of birth. In reply to the above question it may be pointed out, as Peacock has done, that such communications between the two sides of the heart are all important for the continuance of life, even for the shortest period, when the pulmonary artery is occluded.

It is evident, as Peacock has shown, that if Stillé's first and third conclusions are true, as the cases undoubtedly show, the theory of intermixture of the blood does not account for the condition of cyanosis. It is probable in many of these cases with abnormal openings in the septa that the intermixture of the blood is but slight, since if the pressure on the two sides of the heart is equal—and it may become equal through the establishment of a collateral circulation, although primarily it was unequal—no intermixture takes place through the defective septa. Neither does the admixture theory account for cases of intermittent or delayed cyanosis. Such cases can only be supposed to be due to a varying propulsive power or to a subsequent increase of the pulmonary obstruction. Neither does admixture account for localized cyanosis; for example, in the face or in one extremity: this condition, rare as it is, must be due to other causes. Peacock, while combating the admixture theory, considers that Stillé's conclusions in favor of the congestion theory as dependent on obstruction of the pulmonary artery are too exclusive. He discusses also the relationship of congenital cyanosis due to malformation, to cyanosis acquired through pulmonary and cardiac disease as seen in the adult, and shows why the latter condition is rarely ever as intense as the former, and also why acquired obstruction of the pulmonary artery is not necessarily productive of cyanosis. The reason of the difference he believes consists in the compensatory hypertrophy of the right ventricle, with perhaps a gradual diminution of the blood-mass, as seen in some cases.

On the whole, Peacock subscribes to the congestive theory, but thinks that the intensity of the cyanosis is modified by the capacity of the capillaries, by the period of development or duration of the obstruction, by the natural coloration of the skin, and by the color of the blood itself.

Under these two theories, and the arguments offered in support of them, there seems to be no other explanation possible of the condition of blueness, and yet the whole story of the mechanism of cyanosis does not seem clear. Partly, this is due to the incomplete knowledge of the physiology of the aëration of the blood which obtained during the most active period of the discussion of cyanosis and its causation. Let us consider briefly the simplest case of cyanosis. Every child born has in one sense a temporary malformation of the heart—an open foramen ovale which does not close for several days after birth. Every child is born partially cyanotic, owing to compression of the uterine sinuses or pressure on the umbilical cord; it is completely cyanotic if there occurs premature separation of the placenta. The cyanosis continues until the child breathes. The cause of this cyanosis must be looked for, not in the temporary malformation, but in the imperfect expansion of the lungs. As soon as the respiratory function is assumed—as soon as, in other words, the pulmonary-artery branches carry a full amount of blood which becomes aërated in the lungs—the cyanosis ceases, although the foramen ovale is not yet closed.

The closure of the foramen by a trapdoor valve is, as has already been pointed out, not in accordance with the anatomical facts: turning the newly-born infant on its right side does not favor, as it is commonly supposed, the closure by gravity of a preformed swinging lid, which when it has dropped down for ever partitions the right from the left auricle. The right-sided position may favor the expansion of lungs or in other ways promote the pulmonary circulation, but in itself it does not tend to close the foramen. In fact, cyanosis does not here depend on the defective development, but on want of aëration of the blood.

Again, looking to the skin or mucous membrane, what is the condition of the blood and of the circulation which renders the parts of a blue color, and in what do they differ from the normal? In the normal state of the blood and circulation the capillaries of a given area are filled, one half with arterial blood, and the other half with venous blood; that is to say, the capillaries at the point of their origin from the arterioles contain pure arterial blood: as the blood-current proceeds outward the blood becomes progressively less and less red and more and more blue or black; when the venous radicle is reached the blood-current is of as dark a hue as it ever becomes. In general terms, therefore, it may be said, taking the average, that in a given area half the blood is venous, half arterial. Here, then, we see, with an equal mixture of the red and blue blood, nothing resembling cyanosis. It is evident, therefore, that to produce a cyanotic hue the blood must be wholly venous; the intensity of the blueness will vary with the amount of non-aërated blood present in the capillaries. But let us suppose an equal admixture of right- and left-sided blood to take place—for example, when the aorta arises from both ventricles, the pulmonary artery obstructed. It cannot be supposed that the venous blood would retain its dark hue. The contact of the two bloods within the aorta on their way to the capillaries would result in arterializing the venous blood at least one-half, so that when it arrives at the capillary network the intensely blue color of a marked case of cyanosis would have disappeared.

Besides this, there are other considerations to be taken into account to show that neither of the two exclusive theories accounts for the state of the blood and of the circulation in cyanosis. If the condition of the cyanotic parts, due to acquired valvular heart disease or various morbid states of the pulmonary tissue of an acute character be compared with the same parts in cyanosis from malformation of the heart, striking differences are discernible. If the simple condition of cyanosis of the part due to localized pressure on the veins be examined, the differences are even more perceptible. In the malformation there is an admixture of blood; in the other condition there is no opportunity for the intermingling of the currents. In the latter the cyanotic area becomes swollen, and the intensity of the color may become lessened through the oedematous condition; in the former the skin of the cyanotic infant rarely if ever presents any swelling; the veins of the part show little, if any distension, as is so frequent in the latter; cases of malformation in which subsequent endocarditis with additional obstruction occurs may show oedema and swelling similar to cases of acquired valvular disease. In these cases of cyanosis the condition must be due to a want of aëration of the blood, since it never appears until such alterations of the pulmonary tissue and circulation are reached as to render it certain that the blue coloration is due to a want of aëration of the blood. Fulness of the veins and oedema may be present, but never general cyanosis.

Another important consideration in the production of cyanosis does not seem to have been fully appreciated. It is the fact that in all cases of obstruction of the pulmonary artery the collateral circulation, carried on by very varying channels, the bronchial arteries, the oesophageals, the coronaries in some cases, the internal mammaries and intercostal arteries in rare cases, or by the ductus arteriosus Botalli, which alone must be always inadequate in marked narrowing of the pulmonary trunk,—the collateral circulation must always remain insufficient for carrying sufficient blood to the lungs for aëration. Kussmaul was the first to call particular attention to this fact; and it is to this condition of insufficient channels for the blood reaching the lungs that certain cases of cyanosis must owe their causation.

Hence it must be that, in all the complex conditions found in cases of cyanosis from defective development of the heart, a want of due arterialization or aëration of the blood is at the foundation of the state as seen in the cyanotic area. Whether it results in a given case from excessive admixture of venous blood with the arterial when the current reaches the capillaries, or from venous stasis due to central obstruction, of which pulmonary-artery narrowing or closure is the type, or whether from a failure of sufficient blood to reach the lung, as where the collateral circulation remains imperfect, or as seen in certain cases of defective development of the lungs, is most difficult to ascertain. That sufficient consideration has not been given to the third possible factor in the causation of cyanosis—viz. failure of the blood to reach the lung, as distinguished from general venous congestion alone—is evident. That intermingling of the blood from the two sides of the heart must inevitably reduce the red color is certain—that in very many cases the reduction in color does not cause cyanosis can be readily understood from the consideration already offered. The cases of free admixture in which cyanosis does occur may coincide with a condition of very imperfect collateral circulation to the lungs, and hence with a low aëration of blood of the left ventricle, insufficient, therefore, to bring up the color of the blood from the right side of the heart above the cyanotic point.

Whether non-aëration of the blood from failure to reach the lungs, apart from general venous congestion, is a sufficient explanation of the cyanosis in a large majority of cases or in the whole number, is not apparent from the records of reported cases. Much more accurate post-mortem accounts, made with a view to determine the question, than at present exist will be required. In a number of well-reported cases of defective pulmonary artery with a free admixture of blood the pulmonary collateral circulation is found to be well developed, and no cyanosis had appeared, or had been but trifling and inconstant. In other cases of quite as marked pulmonary obstruction with but slight commingling of the blood through abnormal apertures and but slightly-developed collateral circulation, cyanosis has been found intense and constant. In the two conditions the possibilities for general venous congestion are about the same, though perhaps not equal, while the striking difference, apart from the admixture of the blood-current, consists in the conveniences for the aëration of the blood.

The only variety of malformation of the heart in which intense and constant cyanosis must inevitably be present is that very rare form of transposition of the great trunks, the aorta springing from the right ventricle, the pulmonary artery from the left, with closure of the septum ventriculorum; the pulmonary veins enter the left auricle bearing red blood, and the venæ cavæ the right auricle with blue blood; if the ventricular septum is closed, the aorta necessarily carries blue blood to the systemic circulation, and the pulmonary artery is filled with red, carrying it back to the lungs, whence the fluid has just come. In such relation of the principal trunks, even if the ductus arteriosus Botalli and the foramen ovale remain open, cyanosis is necessarily present. The bulk of the blood in the aorta is blue: the only points in which it comes in contact with red blood are, first, at the foramen ovale: here the intermingling is not sufficient to bring it above the cyanotic color; and, secondly, at the ductus arteriosus, and here the tube is not favorably directed for a copious intermingling of the two bloods, neither can it probably ever be sufficient in itself for this purpose. Hence the aortic blood is almost wholly venous. If these two foetal openings did not persist life could not continue beyond a few hours, or even a few minutes, after birth. In such a case the cyanosis does not depend on general venous congestion, and specimens are reported of this sort in which the great vascular trunks were without obstruction, life having been maintained for a few months; adult existence is probably impossible. If, however, with such transposition of the vessels to the improper ventricle, the septum ventriculorum remains widely open, cyanosis may be absent or inconstant, because, apparently, admixture of the blood and also aëration are sufficiently free. But in cases of transposition of the vessels, or even in the much more frequent specimens without transposition, when the track to the lungs is defective either from want of a collateral pulmonary circulation or directly from impervious pulmonary artery, cyanosis becomes more intense and more constant or comes in more frequent paroxysms, irrespective of the presence or absence of evidences of general venous congestion.

It would seem to result from this grouping of facts, and looking at them from a reverse bearing to Moreton Stillé's point of view, that distal rather than proximal obstruction of the pulmonary artery, taken as a type, was the cause of cyanosis. Admixture of arterial and venous blood must reduce the redness of the arterial stream, just as certainly as red paint mixed with black varnish will render the black less intense: whether admixture alone ever produces a deep cyanotic hue of the surfaces is probably more than doubtful; that admixture will prevent constant cyanosis seems certain, when cases of complete transposition of the vessels with open septum ventriculorum are compared with those with closed septum, the other conditions remaining the same. General venous congestion from pulmonary obstruction or other causes outside the pulmonary tissue produces cyanosis, but of a sort quite unlike the typical cyanotic condition of malformation of the heart. It may therefore be doubted if the cyanosis seen in obstruction of the pulmonary artery is due to general venous congestion; it may be wholly produced by conditions on the other side of the obstruction—viz. want of aëration of the blood, which must ever remain the essential feature of cyanosis. This supposition allows of an easy explanation of the difference between cases of apparently equal obstruction of the artery, in some of which cyanosis is present and in others absent; it also allows of the explanation of inconstant or paroxysmal cyanosis where the obstruction, and consequently the venous congestion, is uniform and permanent.

CARDIAC THROMBOSIS.

BY BEVERLEY ROBINSON, M.D.

DEFINITION.—In general, this name is given to every deposit of coagulated blood or fibrin in one or more of the cardiac cavities. By its derivation ([Greek: thrombôsis], coagulation, from [Greek: thrombys], clot) it further implies the manner in which the coagulum is formed and all the morbid alterations connected with it.

SYNONYMS.—Heart-clot. Fr. Thrombose cardiaque; Ger. Blutgerinnungen im herzen; Lat. Thrombosis cordis; It. Trombo; Sp. Trumbo.

The definition offered is not wholly satisfactory, because, although it is accurate as far as it goes, it is not complete. It does not distinguish between concretions of different origin, etiology, mode of formation, and age. No separation is made between fibrinous deposits which increase from the beginning and layer by layer in the cavities of the heart, and those transported there from a distance and forming a nucleus for fresh deposits. To make the definition anything like exhaustive would require many references to the general history of THROMBOSIS AND EMBOLISM; we therefore direct our readers to that article for what relates to the common facts of these morbid processes, retaining for the present only those matters which relate specially to the heart.

Heart-clots may be formed—1, during life, when the patient enjoys, apparently, good health and strength; 2, toward the termination of life, when the general forces are evidently depressed, or at the final stage, when life ebbs low and the agony has appeared; 3, after death. These clots have therefore been divided into cadaveric clots, those of the agony, and ancient clots. To the clots of the agony exception is properly taken, for the reason that agony is a term employed with a somewhat badly-defined signification. At what period does it begin? Is it not frequently of different length? Does it always exist? The answers to these different questions render our objection proper, and show that we had better employ the word terminal for coagula of the second division.

Manifestly, the separate varieties of coagula have not an equal importance. The clots which are post-mortem productions are only interesting for their physical characters, which, fortunately, are well marked, and enable us at once to distinguish them from the two other varieties. The coagula in the first two divisions have an interest both clinical and pathological.

The ancient clots are invariably accompanied with signs and symptoms which should reveal their presence. As much might be affirmed for the terminal clots in the majority of instances and when the patient is not already in extremis. The pathological study of these varieties has great value, and especially in so far as it will the better enable us to distinguish the clots formed some time previous to death—be it of shorter or longer duration—from those which are but the result of the gradual stagnation of the blood-current in a weakened and wellnigh powerless organ. Amongst the clots which are formed in the venous system, some are transported, and pass immediately through the heart, to be arrested finally in some of the larger or smaller arterial trunks, whilst others remain in situ in the heart, and are constantly increased by successive additions or layers of new fibrin or cruor.

The nomenclature to be desired is one which would assign different distinguishing names to each variety of coagulum, so that at once its origin, mode of formation, and perhaps too its age, should be exactly determined. The ancients employed the term polyp for deposits of every description in the heart, but such use of the word was, generally speaking, erroneous, since the true polyp is a very rare disease of the cardiac cavities. Bartholetti and Pissini first made use of it, and considered without doubt that the false polyps or fibrinous deposits in the heart were of analogous nature with the true polypi which are found so frequently in the uterus and nasal cavities. No doubt (as has been inferred) the term polyp in regard to these formations came into habitual use owing to lack of familiarity on the part of the older writers with the varied aspects of clots, as well as their ignorance of the distinct appearance offered by sections from them under lenses of great power. This mistake, therefore, is to-day not to be wondered at, if we duly consider how imperfect and unusual in olden times were pathological researches. Heart-clot was, as will be seen in the historical sketch which follows, the subject of numerous prolonged and animated discussions. As a result of these latter, it was ultimately believed that the great differences of appearance and formation which exist between coagula depend in great measure upon their relative age, and it is for this reason that the basis of distinction between their varieties rests mainly upon the period of time previous to a death at which they are formed. When we speak, however, of polypiform concretion or deposit, we approximate nearer the truth and indicate in a measure the local origin of a coagulum. Many others have employed the terms post-mortem and ante-mortem as being the only suitable terms with which to make a distinction between the coagula formed during active existence and those which are revealed only with the scalpel in the dead-house. In the consideration of this subject the symptoms shall be fully described which indicate the presence of heart-clot found during life, whilst in regard to clots formed in extremis or after death it is desirable particularly to show the pathological characters which shall definitely place them. For all that pertains to embolism of the heart we shall refer the reader, except when it is essential to mention certain details, to other articles in this work. Certain authors have erroneously, it is believed, regarded this subject of heart-clot as one of mere pathological interest, stating that the dead-house is the only place to study its origin and many of its organic effects. This opinion should be combated with vigor. Such a view is far too restricted, and it is here believed that the clinical aspects of cardiac thrombosis are worthy of attentive study, and that something better and further should be attained than merely to watch the downward course of a patient thus affected, and to bear in mind the pathological sequelæ of this disease.

HISTORICAL SKETCH.—The questions which have a present interest in regard to heart-clot are very different from those which formerly engaged medical attention. No longer are we uncertain as to the formation of these coagula during life, nor doubtful as to the various and important effects produced by their transport in different organs through the arterial and venous vessels. Thanks especially to the inaugural thesis of Legroux (1827), to those of Le Marchand and Ball (1862), to that of Bucquoy (1863), but particularly to the experimental researches of Virchow (1846–56) and to the observations of Senhouse Kirkes¹ in regard to the formation and transport of emboli into the cerebral vessels, these facts are all matters of ordinary information. There is little doubt that Galen had noted the formation of intra-cardiac thrombi during life, and attributed to them interference with circulation and respiration, and, at times, sudden death. With the exception of Salius, mentioned by Morgagni as having remarked oedema due to this cause, we reach the sixteenth century before again meeting with any detailed mention of a similar pathological condition. Helidé of Padua, according to some,² Benivenius, according to others,³ were the first authors to give full descriptions of cardiac polyps. This, indeed, was the term affixed for a long period to fibrinous concretions in the heart, beginning with Sebastian Pissini (Milan, 1654), who first employed it. The name took origin, without doubt, on account of their resemblance to polyps of the nasal fossæ, and perhaps to the animal thus named. It was particularly at this period that they acquired their significance, and became the subject of animated discussions between distinguished physicians of the last two centuries. Some, exaggerating their importance, attributed to them the gravest and most important symptoms, although a chronic affection of the heart or lungs present at the time was frequently sufficient to explain them; others, like Kerkring (1670) and Jos. Pasta⁴ (1737), who contested the possibility of the blood coagulating during life, and believed they were invariably cadaveric formations, took from them even a pathological interest. This latter extreme opposition to reality originated very soon a mixed conviction, which was that held by Senac and Morgagni. These distinguished observers recognized that intra-cardiac thrombi formed both during life and after death, the former being rarely encountered. The later, or anatomical school, confirmed these views, but also added testimony to show that ancient and terminal concretions were not phenomena of such unusual occurrence as had been previously held. Testa (1810) and Kreyssig (1824) connected fibrinous deposits with inflammation of the heart, and the last-named writer described a disease which he named carditis polyposa. This view and that of Laennec, which attributed globular vegetations to an inflammatory cause, are in our day disproved. Amongst those authors who rendered certain the formation of cardiac clots during life, we should mention a few others whose names have a special importance in this connection as having made a special study of diseases of the central organ of circulation. These are Corvisart, Burns, Andral, and Bouillaud. Since this period the field of research has become far less limited, and investigations have been made in regard to similar coagulations in the large vessels of the body.

¹ Med.-Chir. Trans., 1844, pp. 281–325.

² Dict. de Méd. pratique, vol. viii. p. 558.

³ Ziemssen's Cyclopædia, vol. vi. p. 292.

⁴ Quoted by Grisolle, Pathologie interne, Paris, 1865, p. 464.

In 1856 a new era was established in regard to these formations, and especially with reference to their transport. Virchow at this period showed conclusively, after long-continued and accurate clinical observations and experimental researches, that a clot formed on the one hand in one of the large veins might be carried to the pulmonary artery and block up more or less completely the supply of blood to the lungs; on the other, that a portion of a thrombus formed in the left heart-cavity might become detached and plug completely one of the arteries of some far-removed organ, as the spleen or kidney, and thus give rise to those ultimate effects which we now understand under the name of infarction. Thus was first established the new pathological ideas which have become familiar with the words embolus and embolism. True it is that Virchow was not the first writer who had described the facts relating to the translation of portions of coagulum from one region to another of the circulatory system, and its fixation in a particular arterial branch. Already this subject had been clearly and succinctly narrated by Van Swieten. A passage in which the causes and mechanism of apoplexy are referred to gives lucid explanation of this doctrine: "Whatever causes change the blood, lymph, and the matter which supplies the spirits, so as they cannot pass freely through the arteries of the brain, but are there impacted. Such are frequently—polypous concretions in the carotid and vertebral arteries, whether first formed about the heart or within the cranium itself."⁵ These ideas of Van Swieten had not, however, produced any very permanent impression, and were almost forgotten, when Legroux (1827) promulgated his view in regard to the possibility of portions of coagulum being carried from the heart into different portions of the arterial system. He published, in fact, two most interesting cases of gangrene of the hand and forearm in which the efficient cause of the disease was found in an obliterating embolus of the brachial artery, which was evidently similar in its nature to the thrombus found in the heart of his patient. It is interesting to remark that Legroux's inaugural thesis, in which these facts were brought to light, was only the forerunner of some very complete articles on the subject of cardiac and vascular concretions, in which he goes over much of the ground which was covered in Germany by the work of Virchow. Legroux published his ulterior researches in the Gazette hébdomadaire, Paris, 1856, pp. 716 et seq. In fact, under the head of correspondence we find in No. 20 of the journal of this year (pp. 349 and 350) an interesting letter from Legroux to the editor, in which he claims for himself the priority of publication (Van Swieten excepted) of the facts pertaining to intra-cardiac thrombi and their effects due to transport of detached fragments into a region more or less removed from their place of development (p. 34). As this claim, according to my researches, appears justified, a part at least of the credit awarded to Kirkes, Virchow, and Schützenberger as discoverers and disseminators properly belongs to Legroux.

⁵ G. Van Swieten, Commentaries upon the Aphorisms of Boerhaave, Aph. mx., vol. iii. p. 159, ed. London, 1774.

In spite, however, of these investigations, and those of Allibert (1828), Louis (1837), Baron (1838), and Paget,⁶ who showed how the blood could coagulate in the heart and by transport block up the pulmonary capillaries, we cannot dispute the glory to Virchow of having in some sort created this study. Owing to his great sagacity, he was able to seal his studies and experiments with the stamp of a master-mind. The new words embolus and embolism introduced by him refer to a process which was previously but badly understood, and which now fix, as it were, a domain in modern pathology. The theory of Virchow found many advocates—many who were opposed to it in the beginning. In consequence of this it was the origin of numerous works undertaken in this new direction. Amongst the most important are the communication of Schützenberger,⁷ the thesis of Lancereaux (1862), the great work of Cohn (Berlin, 1862), the article of Weber in the treatise of Pitta and Billroth—which contains recent theories about coagulation of the blood and the transformation of clots—and the memoir of Polaillon upon cardiac embolism (Paris, 1879).

⁶ Med.-Chir. Trans., 1844, pp. 162–188.

⁷ Gazette médicale de Strasbourg, 1857.

ETIOLOGY.—So soon as the blood is withdrawn from the influence of life it no longer remains fluid, but rapidly coagulates. Thus it is we find frequently after death coagula filling the cavities of the heart and extending in long ribbon-like bands into the larger vessels, more particularly in the veins. What occurs here is very similar to what we notice in a bowl which receives the blood of a venesection. Here the blood thickens rapidly, the clot forms, leaves the sides of the bowl, assumes the appearance of jelly more or less colored owing to the corpuscles enclosed in the meshes of fibrin, and is bathed in a quantity of ambient serum. A similar change takes place in the heart: the serum is imbibed by the tissues and the clot remains in its cavities.

Coagulation of the blood is a very complex problem. Many theories seek to explain it. On the one hand, it has been said the fibrin pre-exists in the blood, and by the fact of the slowing of the circulation, the reduction of the temperature, etc. the fibrin separates from the blood and coagulates. Again, it is admitted that the fibrin does not exist formed in the blood, but that a fibrinogenous material is present which is acted upon by the hæmoglobin or globulin contained in the red globules, the leucocytes, and the corpuscles of connective tissue, and sometimes is, sometimes is not, caused to precipitate as fibrin (Virchow). The exact conditions which occasion the activity of the globulin are unknown. The reaction which takes place has been said to resemble that which takes place between amygdalin and emulsin when prussic acid is formed, or between myrosin and myronic acid when the volatile oil of mustard is produced. Further, it is stated, in accordance with accurate chemical investigations, that the plasma of the blood contains a substance called plasmin, which separates itself into fibrin which coagulates and into fibrin which remains dissolved in the blood (metalbumen, Robin). These fibrins are evidently of two kinds. The plasmin divides itself under the influence of slowing of the circulation, the action of acids, of foreign bodies, of oxygen in excess, etc.; it remains intact in a fluid condition when the vascular walls and globules are healthy, the blood circulating with normal rapidity, and in presence of alkaline principles.⁸ According to Foster,⁹ "Coagulation is the result of the interaction of two bodies, paraglobulin and fibrinogen, brought about by the agency of a third body, fibrin ferment." Schmidt concludes that when blood is shed a number of white and intermediate corpuscles fall to pieces, by which act a quantity of fibrin ferment and of paraglobulin is discharged into the plasma. These meeting there with the already present fibrogen give rise to fibrin, and coagulation results.

⁸ Dict. de Méd. et de Chirurgie pratique, vol. viii. p. 569.

⁹ A Textbook of Physiology, p. 22, New York, 1880.

As regards the formation of clots within the body, it is supposed that injured or diseased spots or foreign bodies first attract, and then, as it were, by irritation cause the death of, a certain number of corpuscles.¹⁰ The views of Schmidt of the fibrino-plastic function of paraglobulin are not accepted by all investigators; and some authors believe that the fibrinogen as well as the fibrin ferment arises from the white corpuscles.¹¹

¹⁰ Pflüger's Archiv, vi. (1872), p. 413; xi. (1875), pp. 291 and 515; xiii. (1876), pp. 93 and 146; quoted by Foster.

¹¹ Frédericq, L., Recherches sur la Coagulation du Sang, Bruxelles, 1877, quoted by Foster.

According to Bristowe,¹² the frequency of sanguineous concretions does not depend upon sex, but is in a certain relation with age. He has remarked, for example, that they are proportionately more often met with at the extremes of life than toward middle age. This might be explained satisfactorily, perhaps, on the supposition that at these periods the circulation is at times very feeble, owing either to congenital feebleness on the one hand or chronic organic affections on the other. At all events, when we seek for the causes which have most influence in determining the formation of cardiac concretions previous to death, we find—I. the mechanical, or those which act specially in slowing the current of blood through the heart. These causes may exist within the heart or may be removed from it. II. The vital or pathological. These causes are of somewhat difficult determination at times, and pertain usually to affections in which there is notable blood-change, in which the quantity of the fibrin has been augmented absolutely or relatively, or to those of infectious type—viz. diphtheria; or to those constitutional in nature—phthisis, cancer, etc. III. The inflammation of the endocardium or endocarditis. This is admitted by Andral, in a note upon the etiology of cardiac concretions in the work of Laennec, as having special importance. Bouillaud also attributed their formation in certain cases to the chemical action of pus which was present in the economy.

¹² Pathol. Society's Trans., vol. xiv. p. 71, quoted by Bartholow.

I. Amongst the mechanical causes we should mention all organic lesions of the heart, all obstacles in the pulmonary circulation, and possibly, by analogy, certain badly-defined lesions of the pneumogastric nerves. All the stenoses and dilatations of orifices, all irregularities of the valves or heart-walls, all depressions or roughened parts of the walls,¹³ may determine the beginning of a concretion. In the same way, a small mass of fibrin deposited on a calcareous valve after transport from one of the veins of the limbs may originate a voluminous heart-clot. Dilatation of the heart, pericarditis, every cardiac change which weakens the contractile power, is a predisposing cause of cardiac thrombosis. Every organic lesion of the heart tending toward that final stage of asystolism so often encountered, and which weakens so greatly cardiac contractility; pouching of different portions of the cardiac wall, or aneurism; pressure upon the right heart by a mediastinal tumor or a sacculated aneurism of the arch of the aorta,¹⁴—all these have great power in producing intra-cardiac thrombi. The mechanism of these different lesions was familiar to Kreyssig, Laennec, and Hope. At the same time it must be admitted that these changes in the heart are not of themselves always sufficient to give rise to fibrinous deposits. We encounter stenoses and regurgitations at orifices very frequently, and concretions, on the other hand, are relatively rare. Moreover, we find heart-clot at times when there is no cardiac alteration. We believe, therefore, that the heart lesion is an aiding factor—that in the last moments of life, when the force of the heart's contraction is weakened and the conditions of the blood favor coagulation, they will act with special power.

¹³ Pathol. Society's Trans., vol. xiv. p. 71, cases by J. W. Ogle.

¹⁴ Walshe, Dis. of the Heart, Lond., 1873.

Among the mechanical causes which are removed or distant should be mentioned all those which interfere with the pulmonary circulation. Such are the effects left behind by pneumonia, pleuro-pneumonia, or the compression of the blood-vessels by old congestion of the lungs. In these cases, when the vis a tergo is impaired somewhat, and an obstacle is placed in the pulmonary capillary circulation, even if cardiac thrombosis does not directly result at first, we may have thrombi form in the pulmonary veins. In the same way, the nervous affections which are accompanied with slowing of the circulation tend to produce coagulation of the blood. All lesions, as we have said, of the pneumogastrics act in the same direction. In proof of this we should cite the experiments of Meyer of Bonn, of Longet, and of Blondet, who produced fibrinous concretions in the hearts of animals by tying or cutting the pneumogastric nerves. At the same time, the heart-beats became more rapid, wavering, unequal, and less energetic than in ordinary physiological conditions. After all, however, all these mechanical causes are but predisposing causes, for they do not always produce cardiac concretions. Frequently, as we have said already, the obstruction to the circulation may be present, and yet at the autopsy no fibrinous deposit be found in the heart. In order that the mechanical causes act efficiently to produce coagula, it is essential that they be aided by the conditions of the blood which favor it.

All concretions do not form with the same rapidity nor are they of the same size. At times their production is sudden, and but a few hours elapse before the fatal termination is reached. Again, it is affirmed that weeks, and even months, may pass before the concretion has reached a volume sufficient to cause entire stoppage of the heart's contractions. In the former category are found, of course, the softer, least consistent coagula—usually, however, very voluminous; in the latter are the smaller, more elastic, and resistant concretions, at times even presenting a stratified structure¹⁵ and surrounded habitually by a clot formed during the latter moments of life, and having a large proportion of cruor in its composition. The heart affected with fatty degeneration should, if we consider its weakened power and deficient contractility, be a predisposing cause of stagnation first, and finally of the formation of intra-cardiac thrombi. As a matter of observation in the dead-house, however, such hearts are not frequently accompanied with fibrinous deposits in their cavities.

¹⁵ According to Legroux, roughening of the walls or valves gives rise to stratified coagula of moderate size, or else to those small clots which deposit on the surface or margin of the valves (Dict. Encycl. des Sci. méd., article "Concrétions sanguines," Paris, 1876).

All diseases which by their nature and duration produce great exhaustion of the vital powers tend strongly to produce fibrinous coagula in the heart. This is eminently true of those which at the same time do not occasion a diminished plasticity of the blood. It is often assumed that mere stasis in the blood-current through the heart is essential to the formation of clots in its cavities, and to lend support to this belief reference is made to the phenomena which take place in bleeding. It is not true, however, that stasis is necessary to coagulation, and the proof is afforded when we take a bundle of twigs and by beating the blood forcibly produce the separation of the fibrin. Besides a slowness of the circulation, there must be, once again, an obstacle in the heart itself, and even then polypoid concretions are not always formed.¹⁶

¹⁶ Gaz. hébdomadaire, Paris, 1856.

II. The Vital or Pathological Causes.—In this class of conditions leading to cardiac thrombosis are included all diseases in which certain special changes have taken place in the blood itself. Among these we should mention, first, certain sthenic inflammatory affections in which the proportion of the plasmin (fibrin and metalbumen) is notably elevated, and in which, on this account, there is a strong tendency to the separation of fibrin from the blood and to the formation of cardiac concretions. In fibrinous pneumonia and acute rheumatism this is particularly true, and amongst the numerous accidents we have to dread in the course of these diseases none strike us with more dread than the possible production of intra-cardiac thrombi. In fibrinous pneumonia this complication is so frequent that Bouillaud has enunciated the following pathological law: "Fibrinous concretions exist constantly in patients who succumb to a frank, acute pleuro-pneumonia, well characterized, which has reached the second stage."¹⁷ According to Raynaud, this is without question a great exaggeration, and results from the confusion this learned author evidently made between terminal clots and those formed some time previous to death. Nevertheless, there is here a proof of the great frequency of coagula occasioned by this disease, and of the strong tendency to their formation which the condition of the blood must afford. What we have said of fibrinous pneumonia and acute articular rheumatism is not true, singular to say, of lobular or broncho-pneumonia. The lesions of this form of pneumonia are those of a catarrhal inflammation of the lung, and the blood does not offer during its course the remarkable tendency to coagulation that is shown in fibrinous pneumonia. Usually, the heart-cavities and the vessels are filled after death with a liquid of a black or violet-brown color, very often sticky.¹⁸ The fibrin in the heart-cavities in pneumonia is fibrillar, and does not present those changes which indicate that it has been deposited for a long while. Moreover, these coagula do not present physical characters which show any considerable degree of age. They are usually terminal coagula, or at least formed within a few days of the fatal termination. Do globular vegetations occur in pneumonia? At times they do, but they are at least very rare as compared with the fibrinous conditions just referred to.

¹⁷ Gazette méd., 1843, vol. xi. p. 270, quoted by Armand, Thèse de Paris, 1857, p. 41.

¹⁸ Damaschino, Thèse de Paris.

There are other general conditions in which there is a marked tendency to the formation of cardiac coagula. In the puerperal state, according to Simpson, it is occasioned by the resorption of many new elements which vitiate its composition and thus occasion this result. In the poisoning following upon glanders or pyohæmia intra-cardiac thrombi are often found. Lancereaux has found in this latter disease fibrinous deposits in the right ventricle and pulmonary artery around small masses composed of pus-cells. In the different cachectic states, such as those caused by chronic Bright's disease,¹⁹ advanced phthisis, and cancer, although we have a diminution in the proportion of red globules, there is present at the same time a relative increase of fibrin; and the consequence is that concretions are often formed in the heart. In fact, it is in these cachexiæ that we often encounter those fibrinous cysts which will be described under the title of Morbid Anatomy.

¹⁹ Here the retention of the excreta is an important factor in the formation of cardiac thrombosis (Bristowe).

Many well-known authors have declared that diphtheria was very powerful in producing fibrinous concretions in the right heart some time previous to death. Among those who have written specially on this subject we would mention Winkler,²⁰ Richardson,²¹ Meigs²² and Robinson.²³ According to the latter writer, elastic fibrinous clots twisted in the valves and adherent to the cardiac walls are developed frequently in children at a period quite removed from that of the agony, and at a time when they are not as yet in a condition of extreme weakness. Except in exceptional instances this influence of diphtheria to produce cardiac coagula is doubted by Parrot.²⁴ He admits its power, particularly when it is complicated with membranous croup, and in these examples he believes the precocious formation of coagula is determined probably by the asphyxic condition. Whilst denying the influence of diphtheria, Parrot freely acknowledges that measles, especially when complicated with broncho-pneumonia, tends to produce cardiac concretions. The same tendency is recognized by Harley in the early stage of scarlet fever where there is high pyrexia.²⁵

²⁰ Die Bluthlumpen dann der Häutiger Bräune, Wien, 1852.

²¹ Med. Times, vol. i. p. 23, 1860.

²² Am. Journ. Med. Sci., April, 1864.

²³ De la Thrombose cardiaque dans la Diphthérie, Paris, 1872.

²⁴ Dict. Encycl. des Sci. méd., vol. xviii. p. 484.

²⁵ Medico-Chirurg. Trans., vol. lv.

Notwithstanding the diminished proportion of fibrin in typhoid fever, and the impossibility of explaining, in many cases, any increase of the plasticity by local inflammatory disorders, cardiac concretions have been observed by Huss, Virchow, and Hardy.²⁶ Bucquoy also relates, after Huxham, an epidemic which reigned at Plymouth in 1742 amongst sailors who came from a long cruise, characterized by dyspnoea, cardiac palpitations, and intermittences of the pulse. Many of those attacked died, and at the autopsies made polypoid concretions of considerable elasticity and adherent to the walls of the heart were found. Another similar occurrence took place amongst the soldiers of the garrison of Rocroy in 1746. Quite a number succumbed after having shown symptoms similar to those of the sailors of Huxham. Cadaveric sections discovered in the left ventricle several hard, consistent cardiac thrombi.

²⁶ Quoted by Bucquoy, Des Concrétions sanguines, Paris, 1863, p. 36.

III. Endocarditis.—Whatever may be the opinion of different authors in regard to the frequency of endocarditis when intra-cardiac thrombi are present, it is certain that if it does exist the explanation of the presence of these deposits is clear and ample. In endocarditis we have both a local and mechanical cause and also a vital condition of fibrinous deposits in the heart. As a mechanical cause we know that often it is the cause of the stenoses of orifice which are present, and that further, by its effect in producing roughening or fissuring of surface, it offers a strongly predisposing cause of the deposit of fibrin. Ulcerative endocarditis acts still more efficiently in this direction, owing to the fact that it produces its effects as much on the surface of the valve, aortic and mitral, near the adherent portion and in the neighborhood of the cardiac orifice, as between its layers. The result is, that the surface is rough, unequal, presenting often cauliflower excrescences, and showing sometimes, in the midst of a mass of fibrin that has become deposited by degrees, portions of a softened, partially-detached valve which was the nucleus of the outer layers of fibrin. Further, endocarditis of both forms acts as a vital and efficient cause of cardiac thrombosis, in that it belongs to the class of inflammatory diseases which occasions an absolute increase in the proportion of fibrin of the blood (from ²⁵/1000, concrete fibrin 3, and metalbumen 22, to ⁵⁶/1000, concrete fibrin 17, metalbumen 36); and also, more especially in ulcerous endocarditis, by the transport of infectious materials into the blood, which still further tend to cause coagulation.²⁷

²⁷ At times there is complete deprivation of epithelium over a limited area, and in rare cases slight ulcerations of membrane. These two conditions are efficient factors of the exudation of plastic lymph.

SYMPTOMATOLOGY.—According to Laennec,²⁸ it is equally erroneous to attribute to cardiac thrombosis many symptoms which properly belong to an organic lesion of the heart (notably hypertrophy) as it is to believe that intra-cardiac thrombi never begin to form until the terminal period of life. According to him, Haller, Vinckler, Staneari, and Bonaroli²⁹ have observed obliterations of the internal jugular vein and carotid artery by very firm concrete fibrin, and he himself has seen a similar production in the inferior vena cava for the space of four fingers' breadth. Although these concretions were evidently formed during life, they occasioned no symptoms indicative of their presence, nor were there any obstructions in the course of the circulation which could explain their origin. Reasoning from these facts and from the phenomena which occur in aneurismal tumors, it seems highly probable that the blood should coagulate in the heart also during life. Later writers frankly admitted that coagulations in the veins caused partial dropsies, a usual instance of which is the white swelled leg, or phlegmasia alba dolens, from obliteration of the femoral vein.³⁰ This is not invariable, for I have seen, in patients who have succumbed to diphtheria, both venæ cavæ obstructed by coagula, without having observed during life either local or general oedema.³¹

²⁸ A Treatise on Diseases of the Chest, p. 183, Philada., 1823.

²⁹ Quoted by Morgagni, Epist. 64.

³⁰ Vide Bouillaud, Archiv. gén. de, Méd., t. ii. et v., quoted by Hope.

³¹ Thrombose cardiaque dans la Diphthérie, Paris, 1872, p. 43.

Scarcely any contemporary author doubts that cardiac thrombosis gives rise to more or less well-defined symptoms. What these are we shall now consider. Of course we are far less liable to-day, when the diagnosis of organic cardiac disease is so accurate, to attribute to intra-cardiac thrombi the signs, physical or rational, which properly belong to them, and which ancient observers could not differentiate. Nevertheless, there are complex cases in which one is at fault even in regard to this problem.

The symptoms of cardiac thrombosis vary naturally with their size, situation, and rapidity of formation. Certain authors have affirmed, for example, that the concretions formed in an auricle cause a greater amount of interference with the circulation than those elsewhere situated. This they do partly by reason of their size and the less contractile power possessed by the auricle, partly because from the auricle prolongations are sent off which occlude the cardiac orifices. When cardiac concretions form suddenly a few days previous to death, they always aggravate all the symptoms of an obstructed circulation.³² If the case be one of pre-existing disease of the heart, they soon obliterate the cardiac cavities and lead to a rapid fatal termination. According to Grisolle,³³ when the concretions are small and form an obstacle neither to the play of the valves nor to the cardiac circulation, they are not revealed by any appreciable functional trouble. The opinion of Grisolle in regard to small coagula is also shared by Legroux, especially when they are fixed at a distance from a cardiac orifice or concealed in a sinus. When, however, the thrombi are larger and interfere more or less with the course of the blood, they occasion very marked symptoms.

³² Hope, On the Heart, p. 486, Philada., 1846.

³³ Pathologie interne, p. 467, Paris, 1865.

Even before the days of auscultation there were certain rational signs which were dwelt upon with much force as showing the presence of cardiac concretions. Thus, Senac³⁴ writes that the patients thus afflicted feel a weight or oppression in the præcordial region which sometimes becomes extremely painful. Palpitations and irregularities of the pulse were also noted as symptomatic of these productions. Laennec believes that coagula of any size may be recognized; "when, in a patient who till then had presented regular pulsations of the heart, these suddenly became so anomalous, confused, and obscure that they can no longer be analyzed, we may suspect the formation of a polypous concretion."³⁵ He further adds that if the trouble takes place on one side alone of the heart, the fact is almost certain. When the coagula occupy the cavities of the right heart, the sounds of the left heart may remain normal whilst those of the right side are more or less distant and muffled (Legroux). Several authors, amongst whom we should mention Legroux, Bouillaud, Barth, and Roger, have mentioned amongst the physical characters which show the existence of intra-cardiac thrombi the sudden development of a blowing murmur limited to the præcordial region or propagated into the aorta. Sometimes this bruit was soft, sometimes harsh and rough. These writers have also noticed, in conjunction with grave general symptoms, the doubling of the first sound of the heart, making occasionally a sort of galloping murmur. As regards the recognition of concretions on one side alone, I acknowledge that after auscultating carefully several cases in which the autopsy showed coagula formed during life, I have been unable to note signs sufficient to justify a differential diagnosis.

³⁴ Traité de la Structure du Coeur, de son Action et de ses Maladies, t. ii. p. 470 et suix, quoted by Bucquoy.

³⁵ De l'Auscult., t. ii. p. 597, quoted by Hope.

The distinction appears to me difficult in like cases, for how explain that a trouble so considerable, even though it exists on one side only, should not influence the entire cardiac circulation? Moreover, it should be emphasized that the phenomena dwelt upon do not always manifest themselves when the cardiac contractions are perfectly normal. The heart-beats may be increased in frequency and the rhythm be changed. The passage, therefore, from a state of relative calm merely to that of extreme agitation is appreciated less readily. This is particularly true of the symptoms usually described as pertaining to the presence of terminal coagula. For here, at a period approximating the fatal termination, it is wellnigh impossible to determine accurately special symptoms. For this reason it is not surprising how authors have varied in their descriptions, and at best none of them are completely full and satisfactory. I have myself many times sought to recognize the blowing murmur given by Bouillaud as a physical sign of cardiac concretions, but in not a single instance have I been able to satisfy myself as to its existence. True it is that the cases I have watched with greatest care were those of children affected with toxic diphtheria, and it is possible, on account of the infrequency of valvular diseases during childhood, that more than once there may have been confusion between the signs afforded by newly-formed thrombi and those which belonged exclusively to a pre-existing disease of the endocardium.

Moreover, these murmurs have been heard and described by too many good observers (Walshe, Flint, Richardson) for any small negative evidence to weigh against that which is very positive. Sometimes they have been but the exaggeration of a bruit previously heard and which characterized an organic affection of the heart. Sometimes the presence of the thrombus has caused the diminution or complete disappearance of the pre-existing structural murmur. Again, these murmurs are discovered for the first time when the other signs indicate the existence of intra-cardiac thrombi. When they are heard under these circumstances they prove positively that the coagula have sent prolongations between the cavities of the heart or into the great vessels, so as to prevent the accurate coaptation of the valves or to obstruct the onward current of the blood. In the first case a regurgitant murmur is occasioned, tricuspid or mitral, which is heard at the apex; in the second case a basic murmur is detected, which is pulmonary or aortic. Usually these murmurs are systolic, although they may in rare conditions be diastolic. The murmurs have been heard more frequently on the right side of the heart, and have pointed by their location of greatest intensity to the obstruction of the infundibulum and pulmonary orifice. They are then basic or suprabasic, and carried upward toward the infra-clavicular region on the left side. These murmurs are heard very rarely on the left side—so infrequently, indeed, that Walshe cannot affirm that he has ever observed clinically one in this region. Theoretically, of course, such murmurs may be heard at any spot in the præcordial region, and with the first or second sounds provided their size and position in relation to orifices or valves could sufficiently account for them. Whilst there can be little question that murmurs do take place in the præcordial region wholly due to the presence of heart-clot, it is probable that their frequency and diagnostic importance is less than superficial consideration would cause one to believe. Thus, Flint³⁶ states that "the presence of coagula may occasion an endocardial murmur, but as a rule it is wanting, probably in consequence of the enfeebled action of the heart." Richardson³⁷ holds an analogous opinion, and writes: "There are sometimes abnormal sounds, but it is difficult to distinguish these from murmurs the results of valvular lesions." Walshe³⁸ is at variance with this view, especially in regard to the thrombal de novo murmur, and has "heard such a murmur when the examination post-mortem showed the fibrinous coagulum as the only probable cause of it."

³⁶ Disease of the Heart, Philada., 1870, p. 280.

³⁷ The Coagulation of the Blood, Lond., 1858, p. 428.

³⁸ Op. cit. (foot-note).

Auscultation.—In the heart the single, constant sign that has been observed consists in the modified tonality of the normal sounds. These are rapid, irregular, muffled, obscured, and distant. There is notable inequality also in the strength of successive beats, which is obviously explained by the great difficulty the blood encounters in traversing the heart. Now, as I have seen in frequent autopsies that the valvular mechanism of the left heart is ordinarily free from any fibrinous deposit, it is readily understood that it can produce the two sounds normal as regards situation and time, but greatly modified in transmission.

Percussion.—Percussion, except in particular cases which are rare, and in which the cavities are much distended by their contents, will only furnish us with negative signs. When the ventricles are swollen by large coagula, the percussion dulness will be extended laterally. As the right cavity is usually the seat of the deposit, it will be particularly marked toward the right of the sternum. In those instances where the area of præcordial dulness had been determined before the formation of the fibrinous concretion this extension becomes a physical sign of great value. It is to Piorry and the use of the plessimeter that we owe whatever of exactness belongs in like cases to this method of examination.

Inspection and Palpation.—The cardiac impulse may be unaffected by the presence of the thrombus, and if it has been regular in rhythm previous to its formation it may still remain so. This condition is infrequent, however, and usually the pulsations become irregular, tumultuous, and rapid. The force of successive beats will also be different. These signs can be determined by the sight and touch.

Pulse.—The characters of the pulse are variable. Sometimes it presents manifest inequalities, occasional intermittences, and is extremely frequent. It may be quite feeble in the beginning, and afterward gain in strength. Sometimes, in spite of its weakness and depressibility, it retains its regularity and its rhythm is unchanged. The coagulum existing in the cardiac cavities, especially on the right side, explains the variations of the pulse. Effectively, at each contraction of the ventricle this chamber, containing a less quantity of liquid blood, projects a smaller amount of venous blood to the lungs. Besides, this quantity is insufficient to replace the volume of revivified blood which leaves the lung with each inspiration. Soon the left cardiac cavities contract with but small power upon an amount of blood below the normal, and yet it is with this supply that the left heart must satisfy the needs of all the organs. The arteries during life become nearly empty, and it is to this condition, as well as to the lack of synchronism between the action of the two sides of the heart, should be attributed the signs we recognize in the characters of the pulse.³⁹

³⁹ Robinson, loc. cit.

In some instances of cardiac concretions the sonority of the chest remains normal. In others it is obviously augmented, and even by percussion very lightly performed a sound of raised pitch is produced. According to Richardson, this acute emphysema is the direct result of an insufficient blood-supply in the capillaries which surround the pulmonary alveoli. Whilst such a condition may often be observed amongst children, it is not unknown with adults. The affirmation, therefore, of Walshe, that it can only be observed in young people, and that in adults its place is supplied by considerable pulmonary congestion, is not exact. Since Richardson first called attention to the exaggerated sonority of the lungs in cases of heart-clot, other observers have also referred to it. Lavirotte (1864) particularly has insisted on it as a proof of fibrinous deposition in the right heart, and has demonstrated with pathological specimens that it was occasioned by the exsanguinated state of the lungs and their hyperdistension with air.⁴⁰ On the other hand, Raynaud⁴¹ states that when the left cavities are the seat of the concretion there is considerable stagnation in the lungs, and they show signs of great congestion. Thoracic percussion becomes less resonant, and subcrepitant râles are heard in an extended area. Sometimes, even, a moderate hæmoptysis takes place. These signs of emphysema on one hand, of congestion on the other, are not spoken of by the majority of writers on this subject; yet when they are present they will serve to fix our diagnosis and render it more certain. With respect to emphysema, especially amongst children, we should mention its great frequency, and on this account perhaps proper value has not been given to it when found at the autopsy of a child whose death has been occasioned by cardiac thrombosis. When the cardiac thrombus is present in the right side of the heart, Legroux⁴² has shown that there will be a more or less turgid condition of the veins of the neck, and perhaps also of the right upper limb. With this distension of the veins we shall remark, according to him, a partial or general infiltration of the subcutaneous tissues. Sometimes the oedematous condition is limited to the face and neck; occasionally it extends below the diaphragm, especially on the right side of the body. The extent of the oedema will depend upon the number and size of the prolongations which are given out by the main coagulum. Occasionally these prolongations have been found not only blocking up the pulmonary artery, but also filling one or both venæ cavæ and branching out as far as the jugular and subclavian veins.

⁴⁰ Congrès Medico-Chirurgical, Lyon, 1864.

⁴¹ Dict. de Méd. et de Chirurgie, vol. viii. p. 573.

⁴² Gazette hébdomadaire, 1856.

In my own observations I have always found the veins of the neck manifest, without in a single instance reaching any great size, and never have I noticed the prominence of the eyes noted by Walshe. In these cases cyanosis was limited, and was notable in a marked degree only upon the lips, the cheeks, and in the upper extremities. The general or local infiltration of tissue I have never remarked, although closely looked for on several occasions. Some authors, indeed, have described a bluish appearance of the entire surface of the body, together with signs of general infiltration. The explanation given of these phenomena is that there is a general obstruction of the capillary circulation, and that the return of the venous blood to the cavities of the heart is rendered almost impossible. In other words, we have here a well-marked asphyxic condition. If this be true, it is only partially so, and there must be great variation in different instances of fibrinous deposition in the right heart. The rational symptom which was for me one of great value in the diagnosis of these cases was that of excessive pallor, not only of the face, but of the limbs and the entire trunk. This pallor appeared constantly to increase until the last moments of life.

Richardson indeed says the symptoms are those of syncope, not of asphyxia. The different processes of life are arrested on account of a simple absence of arterial blood, not owing to the presence of blood unfitted to reconstitute the tissues. The tendency to fainting is probably due, therefore, to the fact that the right ventricle being more or less completely filled by a fibrinous coagulum, the blood is prevented from passing through its cavity and entering the lungs. As a result, there will be but a relatively small portion of blood which becomes oxygenized after each right cardiac systole. When the clot occupies the left ventricle and auricle, there will be a reflux of blood into the pulmonary tissue, thus causing great congestion of this structure. So intense will this congestion become that occasionally hæmoptysis results and pulmonary apoplexy may be developed, due, doubtless, to rupture of the capillary vessels. This condition occurs before the right heart is much or at all obstructed by coagula. We can appreciate that the physical signs must, if properly noted, show manifestly in which cavity the clot is located. If it be in the right heart, anæmia and emphysema of the lung should follow; hence breathlessness and increased pulmonary resonance. If it be in the left cardiac cavity, the lungs become engorged very rapidly, and we should find dulness on percussion, moist râles, and perhaps an equal or even greater amount of dyspnoea.

Difficulty of breathing appears to belong as well to the symptoms which indicate cardiac thrombus on one side of the heart as to those which characterize its presence upon the other. This symptom was first accurately described by Hope, since his day by Richardson and Meigs.⁴³ It has something special in its features which strikes one particularly, but may deceive unless closely observed. It takes place not because the movements of the thorax are interfered with, not because the entrance of air into the lungs is prevented, for the vesicular respiratory murmur is easily distinguished, but because the amount of blood furnished by the pulmonary artery is diminished. The anguish of the patient is sometimes terrible. The nares dilate, the chest expands spasmodically with each inspiration, and the patient is agitated, moans, and shows that extreme craving for air described by Van Swieten in the summæ anxietates. Under these circumstances, Hayden⁴⁴ states, the surface is cold, and often humid with perspiration. Pain and great oppression in the præcordial region have occasionally been referred to, as in the patient of Beau, who said, in placing his hand to his chest, "I have there a weight which has suddenly formed and which stifles me." Often the anxiety is extreme, and the painful sensations continue to increase steadily until death occurs. In rare instances the suffering, when it has reached a certain degree of intensity, may remain stationary, or even become considerably less. If such a respite occur, it is only temporary, however, and the anguish soon recommences. In milder cases sometimes, and apparently after dissolution or disintegration of the clot, the severe symptoms may by degrees disappear, and from this period the patient makes a steady, uninterrupted march toward recovery. I have only lately witnessed a similar example in a youth attacked with typhoid fever, which had reached the third week. There are constant and intense effort to breathe, extreme restlessness, and the patient will throw himself from one side of the bed to the other, and scarcely remain quiet for a few moments. These symptoms are usually more developed when there is concomitant cardiac disease of organic nature, and unless this be present may not be so pronounced as to concentrate attention upon them.