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PREVENTIVE MEDICINE.

PART V.

THE GERM-THEORY OF DISEASE.

Antiquity of the Theory.—In order to make the sanitary precautions thus rendered advisable clearly understood, it should be explained in the first place that the germ-theory of disease, traced by some to the celebrated Pliny, vastly extended by the renowned botanist, Linnaeus, more than a century ago, and since placed upon a scientific basis, particularly through the labors of the celebrated Pasteur, of Paris, and Professor Koch, of Berlin, to whom more than to all of their co-laborers in this important field belongs the honor of proving what had long been suspected, the relation of microorganisms to disease, and removing this subject from one of theory to one of incontestable fact.

The Pasteur Controversy.—Without relating in detail the controversy that Pasteur's announcement made in 1857 that fermentation and putrefaction were brought about by specific ferments and that these were composed of living cells, it is sufficient to state that this assertion led the way for further investigation, discovery and proof, with the result that the microorganisms causing the diseases of relapsing fever, discovered by Obermeier; that of typhoid fever, by Eberth; of diphtheria, by Loeffler; of cholera and tuberculosis, by Koch; of pneumonia, by Friedlander and Frankel, and the origin of many other diseases are now known as the result of the labors of other investigators, whose claims were subjected to the test of the laws formulated by Koch before their character was established as proven.

Germ Laws.—In substance these laws insist (a), "that in order to the acceptance that a specific micro-organism is productive of disease, it must be demonstrated. (b) That it is constantly present in the fluids or tissues of the individual subject to that disease. ( c) Its absence from all other diseases. (d) Its isolation, growth and repeated cultivation on proper culture media. (e) Its power of reproducing the disease after inoculation in susceptible animals."

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Results of Germs in the Body.—The results of the introduction of living organisms into the system are local or general; the local disturbances are of an inflammatory nature caused by mechanical irritations arising from the presence or activities of the organisms and are accompanied by proliferation of cells and the formation of new tissue.

General Disturbances.—The general disturbances may possibly result from (a) nutritive derangement; or, (b) the organisms may cause innumerable foci of local inflammation, producing general disturbance, as for example in tuberculosis; or, (c) by their activities of growth, reproduction, nutrition, etc., they may give rise to poisonous materials (ptomaines, toxalbumins, etc.), which act on the system as any general poison, malaria is probably an example of this class.

Period of Germ Ripening.—The period of incubation is the time between the introduction of the specific organism of a disease (exposure to small-pox for example), and the manifestation of its symptoms.

Increase of Symptoms.—The gradual increment of the symptoms is attributed to the progressive growth of the millions of minute fungoid plants, whose period of greatest luxuriance marks the acme of the attack, and the death and destruction of which correspond to the decline of the disease. The contagiousness of the communicable maladies is accounted for very beautifully by the existence of the immense number of bacteria forming the true seeds of disease, constantly produced, evolved from the affected individual, and carried through the air of a room or house either alone or attached to some of the innumerable epithelial cells, which are being rubbed off by millions from the surface of human bodies.

Absence of Second Attacks.—The general absence of second attacks is admirably explained by the hypothesis that the parasitic fungus on the first occasion has exhausted all, or nearly all, of some peculiar (unknown) organic, ingredient in the body, which is absolutely requisite for its support, according to the very same law that will cause, as every farmer knows, his wheat to fail if he plants it repeatedly in the same ground and neglects to secure a due rotation of crops.

Transmission of Disease.—Hence, according to this doctrine, contagious diseases are conveyed from one person to another by the transplanting of microscopically visible organisms and spores or seeds which have a separate vitality of their own, each after its kind, and which are to be escaped just as one would escape hordes of animal or swarms of insect pests by shutting them out or killing them before they can succeed in fastening upon human bodies.

The Itch Germ.—It is curious how we have seen in regard to small-pox and diphtheria, etc., the same old battle fought which fifty years ago was so strenuously contested by Biett and Morgagni on the one hand; and the microscopists on the other, in relation to scabies or the itch, now universally admitted to be caused by a tiny insect which burrows beneath the human shin.

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Image: ../plates/jpg100/pl0226-01.jpg

BACTERIA (See Adjoining Plate).

Bacteria (Greek, stick.)—Bacteria are the diminutive organisms commonly called MICROBES (Greek, little). They are visible only under a microscope of high magnifying power.

Forms.—There are three recognized forms of bacteria.

Spiralus.—1. The spiral, or wriggling, form, the only form capable of progressive motion.

Bacillus.—2. The stick-like, or straight rod-like form, incapable of motion.

Coccus (berry).—3. Very like, when magnified, a period in print; incapable of motion.

The Plate.—Upper left-hand object. The circle shows the size of the little drop of liquid subjected to the microscope. It is called the microscopic field. Within, in red, is a magnified section of human muscle. In its folds are seen, in white, the encysted spyrala, called trichinae (hairs). They are found in diseased pork, and enter man through the eating of raw or under-cooked pork. Thorough cooking kills them.

The Plate.—Upper right-hand object. This is the trichina magnified, and more mature. It has taken on the spiral form, due to growth, and is consuming the muscle in which it is embedded. It may, in the end, become the much-dreaded tape-worm.

The Plate.—Lower left-hand object. This shows (1) in white, four cells scraped off the intestines, in which cholera germs may lodge. The little dark. objects are the spiralla of cholera. They are found in the intestinal canal and feces of cholera patients.

Form.—They are short, comma-like elements, also in the form of U and S, and again long and spiral. They are capable of motion. They are cultivated in gelatin, agar-agar, blood serum, potato and bouillon.

The Plate.—Lower right-hand object. This shows the bacillus of consumption (tuberculosis). It is rod-like in shape, slightly curved, and rounded at both ends. It is not mobile. It may be cultivated in blood serum, glycerine and agar-agar.

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Size of Disease Germs.—As having an important bearing upon the hygienic precautions instituted, great benefit would probably result from its being understood by every man, woman and child that the contagion of small-pox, scarlet fever, typhoid fever, yellow fever, measles, diphtheria; cholera, and so on, is composed of exceedingly minute forms of life so small that 25,000 of them, placed end to end, would measure less than one inch in length.

Multiplication of Germs.—Bacteria under favorable circumstances multiply with inconceivable rapidity, reproduction occurring most frequently by cell division, this is technically known as fission, constriction taking place in the centre of the cell, with ultimate separation at this point into two separate living beings; from one parent organism, maturity occurring in one hour, a progeny of fifteen millions is theoretically possible in twenty-four hours.

Nature's Law.—It is, however, probable that the same law of the prodigality of nature, exemplified in the spawn of the herring and salmon, holds good, and not more than one spore in a thousand, a million, or a hundred millions, perhaps, has an opportunity to reproduce its species.

Care Required.—As there is no doubt that the contagion of the diseases just enumerated may penetrate into our system by the air that is breathed, the food that is eaten, and especially the water that is drunk, it is obvious that only the most scrupulous care can save us from these extremely minute seeds, or insure their destruction after entrance into our bodies is accomplished. If these germs were singly disseminated, it would be almost impossible to avert constant infection; but as they generally are carried about by winds or currents in aggregations of thousands or tens of thousands, of course the chances of imprisoning them, or otherwise shielding ourselves from them, is largely increased.

Sanitary Regulations.—The obvious deductions from these facts tend to strengthen the urgent recommendations of sanitarians, that every effort should be made, first to prevent these morbific germs from being let loose upon the world; and second, when they have made their escape into the free air or water, to destroy all these forms of life that are likely to come in contact with unprotected persons —that is to say, human beings from whose bodies one crop of small-pox (or cow pox) fungus, yellow-fever bacteria, relapsing-fever spirilla, and so forth, has not already been raised. Each individual affected with small-pox, scarlet fever; diphtheria, or any other of the diseases above mentioned, is, according to this theory, to be looked upon as a sort of hot-bed or forcing-house for the seeds or sports of that malady.

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Germs Grow like Weeds.—Now, these germs, just like the seeds of larger noxious weeds, which, when allowed to gain a foothold in fields and gardens propagate themselves with such immense rapidity, yet with few exceptions, have no power to move of their own accord; and can only develop if they meet with air, moisture, and congenial soil suited to their peculiar requirements—that is, if a small-pox patient is shut up in an airtight room, so that the seeds cannot escape; or if, whilst in the open air, that air is stagnant, so that no seeds are wafted away from the immediate neighborhood of the individual; or if, when carried along by the wind, they are blown away from any human habitations, or are desiccated in a dry atmosphere, baked by the sun's rays or artificial heat, frozen by extreme cold (as seems to be the case with yellow-fever germs); or, finally, if they happen to meet with no persons but those who have had smallpox or been sufficiently vaccinated; in other words, if they do not "fall upon good ground," all this wealth of provision by which nature tries so hard to secure the perpetuation of the poisonous plant causing smallpox in our systems, becomes unavailing, and her malevolent design against our race, carried out with such a prodigality of murderous weapons, utterly fails.

Avoidance of Germs.—The germ-theory of disease teaches that every new case of the contagious maladies is the immediate offspring of a preceding case, and the direct result of exposure of an unprotected human being to the chance of having the spores or seeds of disease implanted in its system, an exposure which it only required sufficient knowledge, sufficient foresight, and sufficient care to avoid.

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