CONCLUDING CHAPTER. AUTHOR’S THEORY OF MALARIA.

It is easier to pull down than to build up; easier to refute than to convince; easier to find fault than to suggest a remedy: and this reflection may occur, and no doubt has occurred, to those, be they few or many, who have perused the preceding chapters of this work. It may now be asked of me explicitly, What is your theory? What is your remedy for the evils complained of? To this I might reply, as the immortal historian of the “Decline and Fall” is said to have done, “If you have read certain chapters of my work with sufficient attention, you may extract from them my meaning and my views;” but as this might imply on my part either a Teutonic love for obscurity in phraseology, or a fear to commit myself to any theory, I shall here sum up in a few words the views I have arrived at after much reflection on the matter, during a long and active life passed in a country supposed to be a hotbed of malaria, the great source indeed of malaria in Western Europe, that land for which nature has done so little and man so much.

1. There floats in the lower strata of the atmosphere in all regions of the earth, but in very various proportions, for reasons already explained, a poison or poisons, generated by the processes which nature adopts for the destruction of past generations, and the reconstruction of those to come; the destruction of the aged, the worn-out, the nearly extinguished; the reconstruction of the organisms springing into life, to occupy the place of those that were! Whether the poison be one or many; whether it be a single species or one of a natural family, does not affect the general conclusions. The diversity of its effects is no proof of diversity in its essential nature or even origin; the living principle is supposed to be of one nature everywhere and for ever; yet see how varied are the results of this principle in moulding the vegetable and animal worlds; how slight are the modifications even in organic elements, which, when called into play, give rise to the most astonishing and unexpected diversity of results. Why should it not happen, then, with the poison, influence, or thing we call malaria, which, modified by a chemical action too subtle for the scientific man to observe, may yet, being so modified, give rise to an intermittent or a remittent, a plague, a cholera, a diphtherite, a scarlatina, a typhus, or a small-pox? Where did so many poisons come from? Whence came the murrains, the vine-plague, the potato-destroying poison, which was not at all new, neither was it confined to the potato? Whence came the pestilences which destroyed the ancient world? which exterminated at once whole species and genera now extinct? Of one thing we may be assured, they did not die a natural death.

2. This poison, whatever it may be, floats in the lower regions of the atmosphere, supported therein by the gaseous products of fermentation, and more especially by the ammonia now proved to exist everywhere in the atmosphere. It is the product, in fact, of the slow combustion perpetually going on in the air, the earth, the waters, wherever, in fact, animal or vegetable organisms are to be decomposed. We call it putrefaction; it is in truth a ferment, and the fermentable matter, that which gives rise to the ferment, is the immediate agent as well as the result (for it is the nature of all ferments to reproduce their process) of this fermentation, accumulated in the lower regions of the atmosphere. Increased to the dangerous point by men’s imprudence or ignorance, quickened by epidemic influences with whose nature we are of course wholly unacquainted, and absorbed by the living tissues, it excites that fermentation, that tendency to putrescence in the living blood to whose results medical men have given so many appellations. At times it is called ague; at times remittent fever; now it is small-pox; and now a fatal diphtherite. To the transit of ferments through the air and to their inhalation by man, I ascribe the diseases usually called zymotic. In ancient primitive times, when physicians were rare,63 and men did not interfere, a poison thus absorbed ran its course from incubation to specific fermentation, with all its results, in a given time, terminating in a crisis which might be calculated and determined; and which might prove fatal or at once remove the disease. A violent perspiration, a severe diarrhœa, a specific and contagious eruption on the surface of the body, proved and effected the elimination of the poison from the system. The ferment had done its work; it had altered the mass of the blood, and the products of the slow combustion (putrescence, rottenness, fermentation) were discharged by the secretions, according to circumstances peculiar to the constitution of the individual: as out of the same materials serpents elaborate poisons of very different powers and qualities, so the ferment, passing through various constitutions, gives rise to various results. It pervades the air and clings to it, nor can it be avoided but by a change of place of residence;64 storms may, and no doubt do, affect it, but they frequently fail in dislodging the poison; intervening wide-spread oceans fail to interrupt its course;65 and as regards the caprice exhibited in its attacks, we have only to reflect on the number of elements, vital, atmospheric, social, and chemical, involved in its full maturescence. Our doubts on all such matters originate probably in the coarse chemical theories and still coarser chemical experiments which prevailed about thirty years ago, and from their influence, from which men’s minds have not as yet escaped. The atmosphere was declared to contain a few wide-spread gaseous elements, and to be unalterable; the air of towns, of theatres, of large heated apartments, crowded with people, was boldly asserted by chemists still alive to be eudiometrically perfect.

§ 1. Discovery of foreign bodies, the remains of animal and vegetable life, and therefore FERMENTABLE, in the air floating over canals, ditches, marshes, &c.—Scientific chemists, as well as the professors of the conjectural art, are occasionally behind the knowledge of the careful, observing, unprejudiced practical men of the day.66 Experience taught me, whilst engaged in other inquiries, that the sulphuretted hydrogen gas arising from the waters of the canals of Holland is quite sufficient to spoil cottons printed with nitrate of lead, used for dyeing yellow with the chromate of potass. The waters of these canals hold this gas in solution in a certain sense, but from May to September inclusive, the gas escapes during the night in great abundance.

At this time vapours arising from the waters and floating over the adjoining grounds, were found to contain minute portions of aquatic plants mingled with the spores of fungi in vast abundance, together with fragments of a membranous and gelatinous substance about to be mentioned. To these must be added the remains of infusoria not to be detected in dried specimens.

The injurious effects of water holding such substances, gaseous and solid, in solution, we overcome by boiling and passing the steam through (heated) iron pipes, and re-converting the steam into water. By this process we get rid of the injurious effects of these foreign matters, gaseous and solid, held in a kind of solution by the water, in as far, at least, as they affect the colours used in dyeing.

During these examinations of the waters themselves, it was distinctly observed that the infusoria and testaceous mollusca, microscopic and otherwise, with which such waters abound, were developed in glutinous membranes attached to the aquatic herbs abounding in these waters; in short, these membranes seem to be the matrix for the growth, nourishment, and production (using the term in a limited sense) of these organized beings; they form an essential condition of their existence.

The plants themselves were now washed in distilled water, and the animal products were the semivalve and bivalve shells of which I have preserved many specimens. The semivalve belong to the natural families Buccinum, Lynceus, Helix, and Planorbis; the bivalve to the Cardiacæ. The semivalves are the most abundant. By filtering the water which remained after the shells had been removed, innumerable minute particles like dust were discovered; these particles were ascertained by the aid of the microscope to be mainly composed of minute fragments of aquatic plants and of the spores of fungi; to these must, no doubt, be added, although not visible when dried, the remains of zoophytes, and of the glutinous membranes forming the matrix of animal aquatic life.

I now endeavoured to obtain the glutinous membrane or matrix in which these testaceous mollusca were obviously developed, apart and distinct from the animals themselves. To attain this desirable point we filled a glass receiver with water containing the aquatic plants and shells, and the gelatinous membrane already spoken of. The receiver was now inverted upon a plate, and water poured into the plate to the depth of half an inch.

In a few days the receiver became filled with gas, forcing the water downwards into the plate on which the receiver rested; and although after the first day we could not discover any of the gelatinous membranes in the lower part of the receiver, yet that in the plate became like a flaky jelly, attaching itself to blades of grass or leaves. The surface exposed to the atmosphere became dry and brittle, and in this state resembled thin layers of gum; the substance thus desiccated strongly resembled jelly.

The glutinous membrane of which frequent mention has been made above, is of a very viscid nature, and when combined with any animal substance in a state of transition or fermentation, it is poisonous. It is, I believe, generally viewed as the matrix for the development of the ova of these shell fish, and considered as a product or secretion of the parent. Into this question I enter not, leaving it, if it be one, to others.

On exposing for a few days some of the larger testaceous mollusca alive to the atmosphere of the room at a temperature varying from 65° to 70° Fahr., strong proofs were obtained that ammonia was produced in the interior of the shell confined therein by the membrane called operculum, sealing, as it were, the aperture into the shell hermetically. On puncturing this membrane the presence of ammoniacal gas could be distinctly traced by the odour.

I submit to the consideration of professed physiologists the following questions:—1st. What are the effects likely to result to man from the inhalation of these microscopic and gaseous products in a state of decomposition, they being certainly present in the vapours arising from the waters of canals, ditches, &c., in many countries, especially during the nights of spring, summer, and autumn? 2nd. What are the evil effects likely to arise to man from the use of such waters as drink, or when employed for culinary purposes? Lastly: As the gelatinous membranes alluded to are the nidus of various forms of organic life, and contain those forms, developed and undeveloped, occasionally in a state of decomposition, to which of the two forms of life, animal or vegetable, or to both, is to be ascribed the deleterious effects on man, and ascribed by physicians to an unknown poison called Malaria, designated by them as “a poison, an influence, a miasm, a thing unknown”? Ferments and putrescence are not “things unknown:” let us adhere to facts.

§ 2. Thus the principle of wasting away by the action of the atmosphere, of the rotting of vegetable and animal substances, first developed by the illustrious Liebig, opened up to me the path to that theory which seems to reconcile the conflicting observations of pathologists,—that vegetable and animal matters do ferment or rot, and that in this state of rottenness they are carried through the air, was with me no longer a matter of doubt; next came the question, as to the effects of such matters on man when inhaled by respiration and conveyed directly into the living, circulating blood, that most complex of all fluids, that mysterious compound out of which nature constructs the animal world.

This slow wasting takes place in any damp place under ground, and the ferments assume the form of vapour when such places happen to be warmer than the open air; it is in this state that the odour is so sensible to us after a hot dry day or during cold nights. There is no smell in rainy or damp weather. It is in the spring and autumn months when ferments from slow combustion abound, aided by the amount of heat and moisture which then prevail, and by the floating of plants. The poison thus generated is known to be the product of a ferment, and like many such products, possesses the quality of fermenting other organic compounds with which it may come in contact. Introduced into the living system of man, it finds in certain individuals the material already disposed to pass into fermentation. It incubates, and this incubation is measured as to time by a variety of circumstances I need not enumerate. In cold countries the incubation is slow, extending over many months; not that the ferment differs, but its action is modified by the existing condition of the accessories to its action and power. The ferment introduced into the blood in autumn may not show its full action on the living fluids until the following spring, or early in summer: in hot countries it is different; there the ferment, aided by numerous adjuncts, acts almost immediately; fever sets in, causing violent reaction of the conservative powers of nature; delirium, coma, vomiting, death. The mass of the blood has undergone a change in all its constituents, and dissolution and putrefaction are swift in reducing the frame, even whilst life is still present, to that state to which all that lives must come at last; whilst the physician loses himself in vague theories of an “unknown poison”—a malaria, a something not strictly a gas, a matter or influence differing from all chemical or other agents known, the scientific chemist steps in, and shows that the subtle matter they so anxiously endeavour to discover, is a process constantly going on before their eyes; a chemical process, universal; the process, in short, on which in a great measure depends the disposal of the dead and effete remains of the organic world; the growth, the nourishment, the renovator of each successive generation of the same world.

§ 3. It may be now fully admitted that ammonia is the active principle or stimulus to vegetable life, as shown by the extraordinary growth of plants in warm damp climates; in these malaria—as we may still call the poison so developed—exists to the greatest extent, as in the Pontine Marshes, by the banks of the Po, Ferrara and Bologna. From various experiments and observations, I have been led to the conclusion that the ammonia constantly present in the atmosphere, and derived from several sources,67 is the chief cause of the activity which the ferment, or poison, displays under different and varying circumstances. There prevails, in truth, an excess of ammonia in such an atmosphere, resulting from the nitrogen uniting with hydrogen; from the decomposition of vegetable matter carrying decayed animal matter along with it; and from the ammonia always existing in the spawn and in the matter of the shells of infusoria. All my researches into the effects which the various gases have upon animal tissues, showed ammonia to be the most destructive; in fact, no animal tissue can resist complete decomposition by caustic ammonia. I conclude, therefore, that vegetable and animal matter in a state of fermentation, and mixed with ammonia, is the cause or essence of that destructive power which physicians ascribe to malaria. Should this fermentable matter pass in a concentrated state into the torrent of the circulation, the globules of the blood are destroyed, and become black; the person is in the cold stage of fever; next, the vegetable matter ferments, causing the hot stage. No one in Holland has any doubt as to the origin of this power, but ascribes it uniformly to the draining of some lake; and it amounts almost to a demonstration that the air under such circumstances is poisonous or injurious to health. It was even foretold by several writers that fevers would result from draining the lake of Haarlem, as took place in the years 1608, 1641, 1727, 1779, from draining various polders.68

If the principles I have announced be correct, the extreme impropriety—not to use a stronger phrase—of carrying on excavations or other extensive works on the muddy banks of rivers, in marshy or swampy forests, during the summer months, must be obvious to all reflecting persons. No work should be done in such places, or in ponds, after the month of April, for it is warm dry weather that sets malaria afloat. But if this ferment—which we may strictly call malaria, as producing a malarious condition of the air—be, as I apprehend it is, the cause of fever, why should not medical men direct their attention more earnestly to the question in how far such a fermentation of the blood may be met by the employment of substances known to resist and counteract fermentation? Are physicians agreed on the nature of fevers, and the best means of curing them?69

Nothing can be more interesting, in a natural history point of view, than to watch the results upon large bodies of water, of attempts, more or less successful, to complete their drainage. Thus during the operations carried on for this purpose at Haarlem, there sprung up in the dry places of the more elevated parts an extraordinary quantity of plants and herbs, which were not seen in the country before they flowered and sent millions of seeds with their diminutive rocket, silky tails into the air. They were too minute to be seen upon grass, but the footpaths were covered with them, and a current of wind might carry them to distant regions, as the sand is carried from the coast of Africa into the track of the Brazilian packets, to such an extent as to make it uncomfortable to walk on deck. It is by no means, therefore, improbable that those errant seeds came from a foreign land, the native produce of other countries. Continuing my observations into the transit of seeds, I have found them to be the cause of shallow canals in England being full of heretofore unknown water-plants, to the extent of impeding navigation.

It is mentioned in the “Kosmos” of Humboldt, that the dust resulting from eruptions of the volcanic mountains in South America was observed in Spain. But if currents of wind thus carry seeds and other matters hundreds of miles through the air, no one can be surprised that the aquatic plants above alluded to floated to England through the air, from Holland; these plants, new to the land of their accidental adoption, bring with them a new corresponding animal life; in due time they come to maturity and die, and now Nature steps in to take up the task, and complete her work; her process is simple in appearance, most complex in its results: a malarious air—malarious at least to man—appears, as it may be, for the first time in the district, ascribed by medical men to every cause but the true one. In their anxiety to discover a cause, they fix on some antiquated drain, or cesspool, or ditch, by the margins of which many generations of a stout peasantry had lived and died; or they dive into the pump-well, and triumphantly exhibit infusoria, not unlikely engaged at the very moment in purifying the water: it never seems to have occurred to them that ferments only appear in certain combinations of the air—under circumstances which only occasionally occur, and that (which is most lamentable to think of, as in the case of London and the Thames) the evil is most frequently of man’s creation.70

The operations of nature when left to herself never vary; they may always be calculated on, foretold, anticipated; on this assured and irrefutable fact all science rests. It is only when man interferes and modifies the elements at work that nature seems to alter her processes; a disturbing agent has been thrust into the machinery, and the mischief it effects must either be counteracted or entirely overcome. So long as the Lake of Haarlem was a lake, or mere, so long were its banks healthy; but drain it partially, and you must be prepared for the result. There is no middle course; that which was once a lake or sea cannot be left in the condition of a putrid, imperfectly-drained, fermenting mass of mud, teeming with animal and vegetable life, and with a material for which oxygen is the natural ferment; it must be arrested by the hands which drained, or attempted to drain it, and converted into a healthy pasture-land or a wheat-field; if left to nature, centuries might elapse before that which was once a sea would become a healthy forest or natural meadow, during which period man, should he persist in residing on its banks, must undergo the penalty of his own want of knowledge.71

CONCLUSION.

In the first chapters of this work I have endeavoured to trace briefly yet succinctly the history of opinion as to the nature of malaria, showing how, prior to the appearance of Macculloch, no one had given to the theory of malaria any definite form. In those which followed I have traced the history of his presumed discovery from the period of its first announcement to its distinct refutation by one of the ablest of statisticians, showing that, notwithstanding this refutation, the physician having, in fact, no other theory to fall back on, persisted in adopting the theory, and, as a natural result, continued to look for and to find in cesspools and ditches, lay-stalls and drains, that unknown and mysterious poison which they had been told by Macculloch was the cause of all diseases. Confounding it with bad odours of all sorts, they sought for remedies in the destruction of bad odours; at times they sealed the sewers and cesspools hermetically and by law: now they opened up and ventilated the sewers and cesspools also by law;72 and lastly, on finding that they had poisoned the air of the metropolis, and that every experiment they made ended in the precisely opposite results to what they had foretold would happen, as a last resource they endeavour now so to dilute the refuse of living beings as to render it, if possible, inodorous at least. This experiment will also fail. Like true Englishmen, they would not let well alone; they would attempt to solve questions by main force, which science, aided by long and careful experience and observation, could alone effect. At last Liebig appeared, and gave to the whole question a new phasis and another basis; that basis rests on an appeal to the great laws of nature, and not on any researches into the occult, hidden, and mysterious laws regulating the building up and the constructing of the various forms of animal and vegetable life. In this grand work the vital force is in action, whereas the destructive processes by which she annihilates her own forms are strictly chemical; there science may be properly said to commence in respect of the great question I now consider; and uniting experience with observation, it seems to lead to the following conclusions, which, if legitimate, will probably stand their ground until overthrown or modified by the larger experience of succeeding ages.

§ 1. Seeing that putrescent, that is fermentable, bodies can and do exert so great an influence on organic compounds when dead (in the sense we consider them), it is not unreasonable to suppose that animal structures and fluids capable of being fermented, may undergo the same process, that is, fermentation, putrescence, and destruction, or decay, whilst forming a part of the living body.

§ 2. As no sane person doubts the harmony which can be shown to exist in all created beings, so it is probable, if not quite certain, that the laws of decomposition must be as regular as the laws of composition; or, in other words, that as the organic matter is without a doubt the same throughout the living world, and as living bodies are built up or constructed agreeably to certain laws, so, undoubtedly, will they be decomposed by laws equally fixed and constant; invariable; and the nature of the material so decomposed will in no shape be affected by those specific differences which bestow on organic nature her beauteous and varied aspect.

§ 3. The final product, whether of composition or decomposition, must be the same in all respectively; the infusoria, as well as the gigantic whale and elephant, are composed, when living, of the same elementary tissues, and, when dead, decompose into elements the same in all.

§ 4. The presence of microscopic animalcules in putrifying substances is viewed by Liebig as accidental, and not essential to putrefaction or to fermentation; but even admitting this, it is certain that animalcules (infusoria) exist everywhere in inconceivable numbers; if water contains these putrescible substances, as it must always do, then the infusoria are also present in the water; let this water evaporate under the heat of the sun, and we have in a fermentable, that is, putrescible, condition countless myriads of infusoria wafted through the atmosphere, and in certain localities (Pontine Marshes, Sierra Leone, the Orinoco, &c.) forming almost a constant, if not a constituent, part of the atmosphere; they pass into living bodies by respiration: hence the hitherto inexplicable phenomena with regard to the influence of locality in the production of disease, whether derived from animal or vegetable remains.

§ 5. Thus these bodies cause disease, not as live matter, but as dead, fermentable, and putrescible. They are not found everywhere, nor are they everywhere liable to pass into fermentation, a certain degree of heat being necessary for the production of this condition. Their evil effects on human life are chiefly felt when man places himself in a false position in regard to them. In pursuit of gain, national or individual, he seeks the deltas of the rivers of hot climates, plunges within the tropics, despising the maxims of the natives of those countries, encamps on or near putrescent marshes, hoping to escape destruction; prances in holiday costume across the Dobrudscha, as if he were on the Champs Elysées or the grassy slopes of Hyde Park, and having carried folly and contempt for the experience of others to its height, pays the sad penalty sure to be exacted by nature from all those who despise her warnings.

These are my opinions, supported, I believe, by facts and figures, and to those who honour me with a perusal of the preceding chapters I beg leave to say, in the words of the ancient poet and satirist—

Si quid novisti rectius istis, Candidus imperti, si non—his utere mecum.