Henry Gradle

“ In the light of the germ-theory, disease is a struggle for existence beticeen the parts of the organism and some parasite invading it. From this point of view, diseases become a part of the Darwinian programme of nature.
The animal body may be compared to a vast colony, consisting as it does of a mass of cells the ultimate elements of life. Each tissue, be it bone, muscle, liver, or brain, is made up of cells of its own kind, peculiar to and characteristic of the tissue. ”

“ In a suitable soil each bacterium grows and then divides into two young bacteria, it may be within less than an hour, which progeny continue the work of their ancestor. At this rate a single germ, if not stinted for food, can produce over fifteen million of its kind within twenty-four hours! More astounding even seems the calculation that one microscopic being, some forty billion of which can not weigh over one grain, might grow to the terrific mass of eight hundred tons within three days, were there but room and food for this growth! ”

“ If we can now reproduce the original disease in other animals by infection with these isolated bacteria, the chain of evidence is complete beyond cavil and doubt. But this last step may not be the least difficult, as many diseases of mankind can not be transferred to animals, or only to some few species.
If we apply these rigid requirements, there are not many diseases of man whose bacterial origin is beyond doubt. As the most unequivocal instance, we can mention splenic fever, or anthrax, a disease of domestic animals, which sometimes attacks man, and is then known as malignant pustule. ”

“ The ideal treatment of any parasitic disease would be to administer drugs which have a specific destructive influence upon the parasites, but spare their host, i.e., the cells of the animal body. But no substance of such virtue is known to us. All so-called antiseptics, i.e., chemicals arresting bacterial life, injure the body as much as if not more than the bacteria. For the latter of all living beings are characterized by their resistance to poisons. ”

“ Having found a suspected parasite in the blood or flesh of a patient, we can not accuse the parasite with certainty of being the cause of the disease, unless we can separate it entirely from the fluids and cells of the diseased body without depriving it of its virulence. In some cases it is not easy, if possible, to cultivate the parasite outside of the body; in other instances it can be readily accomplished. Of course, all such attempts require scrupulous care to prevent contamination from other germs that might accidentally be introduced into the same soil. ”

“ Instead of the mere passive, unwitting efforts with which we have hitherto resisted them, we now begin to fight them in their own domain with all the resources of our intellect. For they are no longer invisible creatures of our own imagination but with that omnipotent instrument, the microscope, we can see and identify them as living beings, of dimensions on the present verge of visibility. ”

“ An infusion of almost any animal or vegetable substance will suffice—meat-broth, for instance—though not all bacteria will grow in the same soil. Such a fluid when freshly prepared and filtered, is clear as crystal, and remains so if well boiled and kept in a closed vessel, for boiling destroys any germs that may be present, while the access of others is prevented by closure of the flask. But as soon as we sow in this fluid a single bacterium, it multiplies to such an extent that within a day the fluid is turbid from the presence of myriads of microscopic forms. ”

“ The invaders, if they gain a foothold at all, soon secure an advantage by reason of their terrific rate of increase. In some instances they carry on the war by producing poisonous substances, in others they rob the animal cells of food and oxygen. If the organism can withstand these assaults, can keep up its nutrition during the long siege, can ultimately destroy its assailants, it wins the battle. Fortunately for us, victory for once means victory forever, at least in many cases. Most contagious diseases attack an individual but once in his lifetime. ”

“ The body is not such a rigid piece of mechanism that the breakage of one wheel can arrest the action of the whole. Within certain limits, any damage done to individual groups of cells can be repaired by the compensating powers of the organism. It is only when this compensating faculty fails, when the body can not successfully resist an unfavorable influence, that a disturbance arises which we call disease. This definition enables us to understand how external violence, improper or insufficient food, poisons, and other unaccustomed influences, can produce disease. ”

“ Each cell represents an element living by itself, but capable of continuing its life only by the aid it gets from other cells. By means of the blood-vessels and the nervous system, the different cells of the body are put into a state of mutual connection and dependence. The animal system resembles in this way a republic, in which each citizen depends upon others for protection, subsistence, and the supply of the requisites of daily life. ”

“ Though the putrefaction-bacteria, or, as Dumas calls them, the agents of corruption, are not identical with disease-producing germs, they are yet not harmless by themselves. Putrid fluids cause grave sickness when introduced into the blood of animals in any quantity. But this is not a bacterial disease proper; it is an instance of poisoning by certain substances produced by the life-agency of the bacteria while decomposing their soil. The latter themselves do not increase in the blood of the animal; they are killed in their struggle with the living animal cells. ”

“ Hence rotting material, teeming with bacterial life, may or may not contain disease-producing germs, according to whether the latter have settled upon it by accident or not. Even if these disease-producing species were as numerous in the dust as the common bacteria of putrefaction, which we do not know, they would be at a disadvantage, as far as their increase is concerned. For experience has shown that the germs of most diseases require a special soil for their growth, and can not live, like the agents of putrefaction, upon any organic refuse. ”

“ Knowing the nature of the poison emanated by such patients, and studying the mode of its distribution through nature, we can prevent it from reaching others, and thus spare them the personal struggle with the parasite. In no instance has the benefit derived from a knowledge of the germ-theory been more brilliantly exemplified than in the principles of antiseptic surgery inaugurated by Lister. This benefactor of mankind recognized that the great disturbing influence in the healing of wounds is the admission of germs. ”

“ But the new breed has only the modified virulence of its parents, and transmits the same to its progeny. Though the form of the parasite has been unaltered, its physiological activity has been modified: it produces no longer the fatal form of chicken-cholera, but only a light attack, from which the animal recovers. By further enfeeblement of the parasite, the disease it gives to its host can be reduced in severity to almost any extent. These mild attacks, however, protect the animal against repetitions. By passing through the modified disease, the chicken obtains immunity from the fatal form. ”

“ We do not know yet in what way our tissues defend themselves, but that they do resist, and often successfully, is an inevitable conclusion. We can show this resistance experimentally in some cases. The ordinary putrefaction-bacteria can thrive excellently in dead blood, but if injected into the living blood-vessels they speedily perish. Disease-producing germs, however, are better adapted to the conditions they meet with in the body they invade, and hence they can the longer battle with their host, even though they succumb in the end. ”

“ The popular notion, that the disease has taken an alleged "poison" out of the body, has just as little substantial basis as the contrary assumption that the parasites have left in the body a substance destructive to themselves. It is not likely, indeed, that an explanation will ever be given on a purely chemical basis, but in what way the cells have been altered so as to baffle their assailants in a second attempt at invasion is as yet a matter of speculation. ”

“ During their growth the bacteria live upon the fluid, as all other plants do upon their soil. Characteristic, however, of bacteria-growth is the decomposition of any complex organic substances in the fluid to an extent entirely disproportionate to the weight of the bacteria themselves. This destructive action occurs wherever bacteria exist, be it in the experimental fluid, or in the solid animal or vegetable refuse where they are ordinarily found. It constitutes, in fact, rotting or putrefaction. ”

“ Relapsing fever is another disease of definitely proved origin. If we mention, furthermore, abscesses, the dependence of which on bacteria has lately been established, we have about exhausted the list of human afflictions about the cause of which there is no longer any doubt. Some diseases peculiar to lower animals belong also to this category. The classical researches of Pasteur have assigned the silkworm disease and chicken-cholera to the same rank. ”

“ The entire class of contagious diseases of man can be suspected on just grounds of being of bacterial origin. All analogies, and not a few separate observations, are in favor of this view, while against it no valid argument can be adduced; but it must be admitted that the absolute proof is as yet wanting. Many diseases also, not known to be contagious, like pneumonia, rheumatism, and Bright's disease, have been found associated with parasites, the rôle of which is yet uncertain. ”

“ There can be little doubt that in many, perhaps in most instances, the disease-producing germs enter the body with the air we breathe. At any rate, the organism presents no other gate so accessible to germs as the lungs. Moreover, it has been shown that an air artificially impregnated with living germs can infect animals through the lungs. ”

“ The resistance or want of resistance which the body opposes to its invaders is medically referred to as the predisposition to the disease. What the real conditions of this predisposition are, we do not know. Experience has simply shown that different individuals have not an equal power to cope with the parasites. ”

“ In the expectation of all who are not blinded by prejudice, the field is a vast one, which the germ-theory is to cover some day, though progress can only continue if we accept nothing as proved until it is proved. ”

“ But real contradictions do not exist in science; they are only apparent, because the results in any opposite cases were not obtained under identical conditions. The explanation of the variable effects of common putrefaction-germs upon animals is self-evident as soon as we admit that each parasitic disease is due to a separate species of bacteria, characteristic of the disease, producing only this form and no other affection; while, on the other hand, the same disease can not be caused by any other but its special parasite. ”

“ Bacteria surround us from all quarters. The surface of the earth teems with them. No terrestrial waters are free from them. They form a part of the atmospheric dust, and are deposited upon all objects exposed to the air. It is difficult to demonstrate this truth directly with the microscope, for in the dry state bacteria are not readily recognized, especially when few in number. ”

“ In fact, one of the arguments used against the germ-theory—a weak one, it is true—is, that, while it explains why some fall victims to the germs, it does not explain why all others do not share their fate. ”

“ But even yet some botanists claim that all bacteria are but one species, appearing under different forms according to their surroundings, and that these forms are mutually convertible. The question is a difficult one to answer, since bacteria of widely differing powers may resemble each other in form. Hence, if a species cultivated in a flask be contaminated by other germs accidentally introduced, which is very likely to happen, the gravest errors may arise. ”

“ The chicken is almost proof against splenic fever. This protection Pasteur attributes to the high normal temperature of that animal, viz., 42° Cent. At that degree of warmth the anthrax-bacillus can yet develop, but it is enfeebled. The cells of the bird's body, thriving best at their own temperature, can hence overcome the enfeebled invader. Reduction of the animal's temperature, however, by means of cold baths, makes it succumb to the disease, though recovery will occur if the normal temperature be restored in due time. ”

“ SCOURGES of the human race and diseases are attributed by savages to the influence of evil spirits. Extremes often meet. What human intelligence suspected in its first dawn has been verified by human intelligence in its highest development. Again, we have come to the belief of evil spirits in disease, but these destroyers have now assumed a tangible shape. ”

“ The existence of a parasite in this affection in the form of minute rods and its power of reproducing the disease are among the best-established facts in medicine. It is also known that these rods form seeds, or spores, as they are termed, in their interior, after the death of the patient, which germinate again in proper soil. These spores are the most durable and resisting objects known in animated nature. If kept in the state of spores they possess an absolute immortality ”