CHAPTER III.

THE REASONABLENESS OF THE APPLICATION OF THE FACTS TO THE INFERENCE.

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SECTION I.

THE CHEMICAL THEORY OF EPIDEMICS UNTENABLE.

It has been inferred that the germs of disease possess the property of vitality, and a number of facts have been adduced to support the proposition that vitality is the indwelling force by which the matter generating epidemic and endemic disease exercises its influence over man and animals. The reasonableness of the application of these facts to the end in view has now to be considered. Chemistry cannot account for epidemics.

Our first subject of reflection points to the chemical discoveries of the last few years, and particularly to those of the great German chemist Liebig. We find in the first paragraph of his Organic Chemistry applied to Physiology and Pathology, the following words: "In the animal ovum, as well as in the seed of the plant, we recognize a certain remarkable force, the source of growth or increase in the mass, and of reproduction or of supply of the matter consumed; a force in a state of rest. By the action of external influences, by impregnation, by the presence of air and moisture, the condition {109} of static equilibrium is disturbed. This force is called the vital force, vis vitae, or vitality."

The doctrine of Liebig, that the vital force manifests itself in two conditions, or rather, that it is known to be in two different states, that of static equilibrium as in the seed, and in a dynamic state, as in that of growth and reproduction, is perfectly applicable to the germs of disease; the static equilibrium is referrible to the matter of vaccine lymph when dried and preserved for use, and the dynamic forces of the matter are known to be in operation during its reproduction and growth in the system of the vaccinated child.

Then as to reproduction of matter by any chemical process, our author can furnish us with no examples, for even in his explanation of the causes of disease he is quite silent on this point, merely acknowledging that diseased products must be either rendered "harmless, destroyed, or expelled from the body." He further says, that "in all diseases where the formation of contagious matter and of exanthemata is accompanied by fever, two diseased conditions simultaneously exist, and two processes are simultaneously completed," and that it is by means of the blood as a carrier of oxygen that neutralization or equilibrium is established. Liebig thus admits that an agent exists in the blood, capable of deteriorating it at the expense of the oxygen, which he maintains is contained in the red globules; he further acknowledges that two processes of diseased {110} action are going on at the same time, and though he does not explain them, I imagine him to mean that new contagious matter is generated and eliminated from the blood, and that at the same time, there is that condition of body which he would call simply a diseased state, and characterizes it thus: "Disease occurs when the sum of vital force which tends to neutralize all causes of disturbance, (in other words, when the resistance offered by the vital force) is weaker than the acting cause of the disturbance."

If I rightly apprehend his notions, they perfectly harmonize with my ideas, to a certain extent, on the subject. They accord, at any rate, most completely with the theory attempted to be established, and fully confirm the reasonableness of the application of the facts recorded to the inference drawn from other sources. The difference only rests on the question whether vitalized or non-vitalized matter is the fons et origo mali.

How is the production of new matter, resembling that originally causing the disease, to be explained by any known hypothesis, except on the assumption of living organized matter? Though Liebig and Mulder both deny the fact, that the Torula cerevisiae is the sole agent in the process of fermentation: they both equally fail in shewing upon what it does depend, and their difficulty rests entirely on their incapacity to explain the uniform reproductive properties of the matter engaged in this, as well as in all other allied operations. Liebig's statement {111} however on this matter requires notice--he says, "that putrifying blood, white of egg, flesh and cheese, produce the same effects in a solution of sugar, as yeast or ferment. The explanation is simply this; that ferment or yeast is nothing but vegetable fibrine, albumen or caseine, in a state of decomposition."

This state of decomposition, however, involves a much more complex proceeding, than simply a reduction of matter into its elementary forms of gases, earths, and minerals; for we nowhere find decomposition of this kind going on without the development of some organized bodies, either animal or vegetable: and since we have seen that the spores of the cryptogami are always in existence in the atmosphere, and making their appearance under favouring conditions, and especially when we find that fermentation is invariably accompanied, and I may safely say, preceded by the deposition in the fluid of the sporules of the Torula, we can hardly believe that they are any other than the sole agents of the process. I have now a considerable quantity of the Torula obtained from the urine of a diabetic patient, in which they appeared, as it were, spontaneously. After the urine had been allowed access to the air for a certain time, and the whole of the saccharine matter was converted into new compounds, reproduction of the Torula ceased;--and those which remained when the process was completed, still continue as organic cells, deposited {112} in the bottle in an inert state, but ready, on the addition of fresh sugar, as has been proved, to resume an active existence. These germs, it is now well known, may be dried into powder, so as to be blown away like dust without any, or but little, detriment to their vital energies; and there is now no doubt that they exist in this condition in the air, as do the spores of mucor, aspergillus, oidium, agaricus, and all other fungi.

Mulder, however, does allow some properties to the yeast vesicle; he says, "a variety of strange ideas have been entertained respecting the nature of yeast; recent experiments have convinced me that it undoubtedly is a cellular plant consisting of isolated cells. They resemble the composition of cellulose in some respects, but differ from it in many." "These vesicles, consisting of a substance resembling that of cells, do not contribute in the least to the fermentation, but are exosmotically penetrated during fermentation by the protein compound." These chemists seem to have an instinctive horror of allowing any active properties to the yeast vesicle, that is as far as the conversion of sugar into carbonic acid and alcohol is concerned in the act of fermentation. Dr. Carpenter, as if desiring to conciliate the chemical and physiological disputants, considers that the truth is to be found in the mean of the two extremes,--that is, that the process of fermentation is neither entirely dependent on chemical laws, nor on those laws which preside {113} over the growth of reproductive matter, but is a process in which both perform certain offices, each depending on the other to produce the combined result; he thus approaches more nearly to the theory of Mulder, than that of Liebig.

But to revert to Mulder, he speaks of the Torula cells being "exosmotically penetrated during the process of fermentation by the protein compound." Now the Torula is acknowledged to be one of the Fungals, and the chemical constituents of the Fungi approach very nearly that of animal tissues. They contain a peculiar principle, residing in and obtainable from them, termed Fungin, which is as highly azotised as animal fibre. The protein compound alluded to, Mulder says, is not gluten, because insoluble in boiling alcohol, and not albumen, because it is very readily dissolved in acetic acid, and he regards it as a superoxide of protein. This superoxide of protein can only have been produced by a vital action in the cells of the Torula, and as the fungi consume oxygen, and give out carbonic acid, we clearly have all the elementary conditions for their growth in almost all decomposing animal and vegetable matters. It is the nature of the fungi to live on organized matter, but always when it has a tendency to decay; it is for this reason they have been called "Scavengers." Again, we can understand why some animalized or nitrogenous matter should be necessary for fermentation, otherwise fungi could not grow, nitrogen being an essential constituent of {114} their structure, and further fermentation does not commence without the presence of oxygen, and like as in animals, this gas supports their existence. The conversion of sugar into alcohol is represented by the following formula:--

RESULT. Sugar. Alcohol. Carbonic Acid. Hydrogen 3 3 Oxygen 3 1 2 Carbon 3 2 1

If therefore the process were merely of a chemical nature, where is the necessity for atmospheric oxygen to accomplish the end? it is quite certain that fermentation cannot go on without its presence. Let us compare the action of ferment or yeast in a dried state to the action of albumen, which Liebig says is sufficient when decomposing to set up fermentation. "The white of eggs when added to saccharine liquors requires a period of three weeks, with a temperature of 96deg F. before it will excite fermentation." But any saccharine liquor on exposure to the air, though entirely destitute of albumen or gluten, will ferment, and the Torula may be found in it. I have found the Torula in a great variety of syrups which have spontaneously undergone fermentation. I have also discovered that the development of the cells is delayed or accelerated by the nature of the ingredient used in flavouring {115} the syrups, with other peculiarities which need not here be mentioned.

But the conversion of starch into sugar by means of gluten requires some notice, as by some persons it is associated in their minds with the organic process of fermentation. Mulder ascribes the latter in the first instance to the action of heat, evidently believing that the pseudo-catalytic operation of gluten upon starch is the type of all such actions, and regarding them all as simply chemical, but we here distinguish a wide difference; in the latter instance the gluten is decomposed, and rendered unfit for a repetition of the chemical phenomenon, and if it is desired to renew the action fresh gluten must be obtained, and a certain temperature kept up, otherwise the experiment fails. How different is fermentation: in the ordinary temperature of the atmosphere the yeast vesicle will multiply, no incremental or unnatural addition of heat is requisite, and it is one of the commonest and most natural instances of vegeto-chemistry: the grape cannot shed its juice, nor the sugar cane its sap without admitting these germs, which, under certain {116} conditions multiply themselves and convert the saccharine elements into new compounds. The method by which the conversion of starch into sugar is accomplished is thus described by Dr. Ure. He says that if starch one part be boiled with twelve parts of water and left to itself, water merely being stirred in it as it evaporates, at the end of a month or two in summer weather it is changed into sugar and gum, bearing certain proportions to the amount of starch used. But "if we boil two parts of potato starch into a paste, with twenty parts of water, mix this paste with one part of the gluten of wheat flour, and set the mixture for eight hours in a temperature of from 122deg to 167deg F. the mixture soon loses its pasty character, and becomes by degrees limpid, transparent, and sweet, passing at the same time first into gum and then into sugar."--"The residue has lost the faculty of acting upon fresh portions of starch."

Four points of contrast present themselves for notice as elements of comparison with true fermentation. 1st. The starch solution has to be boiled, so that heat, by which it is to be supposed that the starch globule is ruptured, seems to be an essential portion of the chemical change, and even this may in fact alone be sufficient in such a case to produce some elementary change in the starch, and may prepare it for the subsequent catalytic action of some related organic, though not vital material. {117} 2nd. Not only a summer heat is necessary, but a period of one or two months time must elapse before the starch with the water simply becomes converted into sugar, and if artificial heat is to be used to hasten the operation, a temperature from 122deg to 167deg F. must be resorted to in order to obtain the desired result. 3rd. When even this is accomplished there is no reproduction of the fermenting matter, and artificial and chemical means must again be applied to repeat the experiment. 4th. The conversion of starch into sugar can be accomplished without the presence of gluten at all, by the aid only of temperature and time. It seems to me, therefore, to be entirely unnecessary to occupy more space in the elaboration of a proof of the doctrine that the germs of the Torula are the sole agents in the conversion of saccharine fluids into alcohol and carbonic acid. By another chemical process starch can be converted into sugar, but I am not aware that hitherto any method has been discovered by which sugar can be converted into alcohol except by the process of fermentation proper.

I have been thus particular in commenting on this subject, as it bears, in an especial manner, on the question under consideration.

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The physiologist cannot afford to lose this process from the category of chemico-vital, or biochemical manifestations. The philosophy of the age has a tendency to make every thing chemical; it is true that the Divinity is as much seen in the laws which govern the elementary particles of matter, as in those laws which preside over the transmutation and sustentation of those elementary and inorganic particles, when compounded in the tissues which are engaged in the formation of living beings. The laws by which acids and alkalies neutralize each other, and the affinities single, double and elective, which the particles of matter exhibit, together with the influences of light, heat, and electricity upon almost every condition of matter, are as truly wonderful as the creative power. Man may, in many instances, imitate the processes of nature, he can render iron magnetic, and form alkaloids, but the {119} laws which govern the particles of matter are still the secret of the whole proceedings. We do but interpret the language of nature in discovery, the book is ever open before us, and every atom of the world is a word and a theme, capable of occupying the short span of sublunary existence allotted to man. We have read of "sermons in stones," but a book has been written on a "pebble."

To return, as we every where in nature find a gradual transition in the forms, arrangements and properties of matter, so we may expect to find a link between the inorganic and vital chemistry of nature. The fungi, by which we contend this transition appears to be accomplished, are also a link in chemical composition, between the animal and vegetable kingdom, and not only in that, but in their subsisting upon matter which has been organized, they are deoxidizers and reducers, as the vegetable kingdom in its highest function is a compounder. To their functions and offices in the great scheme of creation, we may fairly apply ourselves with a sure and certain result of the most interesting discovery. Is it no hint that wherever decaying organic matter is found, there do we find fungi? is it no hint that they are found in all parts of the world? that even in snow the germs of fungi will grow and multiply to such an extent, according to Capt. Ross, that the protococcus was seen {120} by him, clothing the sides of the mountains at Baffin's Bay, rising, according to his report, to the height of several hundred feet, and extending to the distance of eight miles?

Even stones contain in their interior, or interspaces of their structure, the germs of fungi. A species of Tufa is found in the vicinity of Naples of a porous texture, which, when moistened and shaded, produces vast mushrooms, four or five inches high, and eight or ten inches broad. This author further says: "In the Maremma, where the volcanic tufa is the basis of the soil the surface is intermixed with the animal remains of departed empires, and the ordure of cattle, is covered with grasses of old pasturages, and is wet with heavy dews. Everything, therefore, conspires there to a fungiferous end."

They are found growing in and upon both vegetables and animals. Nees von Esenbeck imagined, that minute forms multiplied themselves in the atmosphere; and really, when we consider the amount of effluvia composed of the atoms cast off from the bodies of living or decaying organic matters, which are incessantly passing into the atmosphere, the conjecture is not an unreasonable one. The minuteness of those, which we know are always found growing on decomposing bodies, does not preclude the possibility, nay, further favours {121} the probability, that others infinitely more minute, may be destined to remove the more subtle and vaporous particles which escape into the air.

We can, therefore, I think, conclude, that the lower tribes of vegetation, may consistently be regarded as capable of existing in almost any condition, and almost under any circumstances, they may be made to grow in plants by inoculation, as shewn by De Candolle, and Dr. Hassall. If the stem of wheat also is inoculated with vibriones, they will make their appearance in the grain. If the seed contain them and have not lost its germinating properties, these worms will be found again in the grain. If the grain containing them be dried for years, and moistened again with water, these animalcules, according to Bauer and Steinbach, will present all the phenomena of life. This experiment I have witnessed, and can confirm the statement. These animalcules in the diseased grain, have under the microscope the appearance of an immense {122} number of eels crowded together in a small space, and presenting a movement more, perhaps, vermicular than any other, and it is continued for a considerable time. Now if these animalcules, or their ova, can be proved to pass with the sap to the seed, there can be no difficulty in comprehending how germs, considerably more minute and of a vegetable nature, should be found subject to the same peculiar mode of obtaining an entrance into animals and vegetables for sustenance. "It is usually imagined," says Dr. Carpenter, "that the germs liberated by one plant are taken up by the roots of others, and being carried along the current of the sap, are deposited and developed, where vegetation is most active."

The chemical theory of disease would be better sustained by a comparison of "the artificial formation of alkaloids," and the phenomena of transformation of blood into the tissues of animals, and their degeneration into effete matters, and of sap into the tissues of plants and their degenerations.

Professor Kopp of Strasburg, says, "In a chemical point of view, the alkaloids are remarkable for their composition, for their special properties, both physical and chemical, and for the interesting reactions to which many of them give rise, when exposed to the influence of different reagents. Considered medically, the organic bases are distinguished by their energetic properties. They {123} constitute at the same time, the most violent and sudden poisons, and the most valuable and heroic remedies."

Upon this very intricate and interesting part of chemical philosophy, it is rather dangerous to enter without a thorough and practical knowledge of the subject. This, however, falls to the lot of few men. We, who are engaged in the study of disease, and of the best methods of cure, are obliged to take the investigations of the analytical chemist, and examine them for ourselves in the intervals of leisure allowed us during the active exercise of our calling. Though with less advantages for the study of these transcendental relations of organic and inorganic matter, we are not, nevertheless, precluded from forming our opinions on their practical bearings to the phenomena and treatment of disease.

That there is a matter of a poisonous nature concerned in the production of endemic and epidemic affections, cannot be doubted by any one; I believe indeed, that the chemical theorists admit this, at all events Liebig does, for he says, "The morbid poison changes in the blood are fermentative, just such as occur in beer making." If we start, then, with the consideration that poisons, in a chemical point of view, are the objects of our research; the obvious course to take is to enquire what is the source of poisons generally, and what their effects on the animal economy? The mineral poisons are entirely excluded from the enquiry by their {124} inaptitude for diffusion, and their uniform effects upon all persons, differing only in degree in their operation. The same objections apply to gaseous poisons, except that to them the property of diffusion would be admitted. We come then to the alkaloids, which constitute, as Kopp says, the most violent and sudden poisons. For the production of alkaloids by artificial means, organic products of some kind are required. Artificial heat, powerful chemical agents or length of time, are, as far as information at present extends, the indispensable requirements to induce these peculiar changes in matter. The only instance I can find, in which elementary matters can by artificial means be combined, so as to resemble the products of nature, is that of the conversion of carbon and nitrogen into cyanogen. But the process by which this is accomplished, leads rather to doubt whether it be really and simply by a combination of elementary carbon and nitrogen. I extract the following from the Annual Report of the Progress of Chemistry, for 1848. "H. Delbruck has performed some experiments on the important subject of the formation of cyanogen. He confirms the statements of Desfosses and Fownes, inasmuch as a weak but distinct formation of cyanogen was observed on igniting {125} sugar-charcoal with carbonate of potassa in an atmosphere of nitrogen." The use of sugar-charcoal, may be perhaps an explanation of the weak formation of cyanogen, for in these numerous and successive chemical changes of matter, it is impossible to say how many sources of error may arise. The constant contradictions of each other, and the opposite statements made by chemists, of equal eminence, leave us in a wilderness of doubt, from which we are not likely to be freed, until definite laws shall be discovered to act as a guide in the comprehension of the higher branches of Chemical Philosophy.

But supposing that the generation of alkaloids could take place in the body, or some analogous poisonous matter, we have yet to imagine a whole host of peculiar and essential conditions to effect this change, besides an atmospheric agent or agents to set in motion those compositions and decompositions, capable of bringing out these new products from the elements of blood. We are aware that in the blood, carbon and nitrogen are sufficiently abundant as well as saline compounds, to generate cyanides, and, with hydrogen also there in plenty, hydrocyanates, and thus from them many other poisonous products, but how is all this to be effected? And even if effected, it is yet a question if such compounds can in any way simulate the attacks of epidemic disease. We have {126} already shewn that the amount of most poisons necessary to destroy an individual, can be pretty clearly estimated, and their modus operandi is tolerably well understood. Again, the most essential part, in which all chemical theory fails, is an explanation of the reproduction of contagious matter.

The catalytic process, by which decompositions are said to be effected, and in which Liebig includes the various fermentations, is one of those chemical relations of matter to matter, considered by some as the probable cause of infection. Mr. Simon, in a late lecture, has said, "I consider the phenomena of infective diseases, to be essentially chemical, and I look to chemistry to enlighten the darkness of their pathology. Qualitative modifications, affecting the molecules of matter as to their modes of action and reaction, are such as form the subject of chemical science; and those humoral changes which arise as the result of infection clearly fall within the terms of its definitions." Further on he adds: "The phenomena of infected diseases appears then, in many respects, to be sui generis. Certainly they are chemical. Probably they belong to that class of chemical actions called catalytic."

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It is not improbable that something resembling a catalytic action may take place in the blood in those diseases of endemic and epidemic origin, but that it can be by a chemical process alone is contrary to all experience of catalytic operations, for except in the instance of fermentation proper, there is no multiplication of the fermentative matter. The action of the matter of contagion seems to stand on the confines between electro-chemical and bio-chemical manifestations, and so long as no chemical explanation can be given for the multiplication of the matter of infection, the most rational course to adopt is to assume that life under some unknown form is, as we every where find it, the sole reproductive agent.

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