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Page:Popular Science Monthly Volume 65.djvu/305

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which he examined on autopsy, of people who had died of all sorts of disease, besides those dying of old age.

There are two conditions essential to the development of consumption. In the first place, there must be the presence of the bacilli of Koch as its specific or essential cause. In the second place, the body must be predisposed to the disease by various unhealthful factors, such as vicious heredity, alcoholism, poverty and the like. Most of us are able to resist the bacillus because our bodies are sufficiently strong to resist the organism, and because there are in our tissues certain germicidal properties, which are ordinarily sufficient to cope with and destroy the bacillus. The layman will easily get the idea from the following experiment: Some rabbits were inoculated with tubercle bacilli and placed in relations generally deleterious to health; these became consumptive. Another group, selected from these same rabbits, were likewise confined, but were not subjected to infection, and these did not develop the disease. Whilst among a third group, which were inoculated like the first, but which were, on the contrary, favorably located as to hygiene, most of the rabbits escaped the disease.

The tubercle bacillus is indeed originally a saprophyte, feeding upon dead or decomposing material. Its next congenial habitat is such tissue of living animals as has been previously devitalized by unwholesome factors; that is to say, these factors have rendered the tissues of the body vulnerable to the onset of the bacillus and certain other microorganisms which later join it in its work of devastation. These predisposing factors render the tissues a fruitful soil in which the bacillus and its allies may germinate and thrive. I should like to touch briefly upon certain of these predispositions.

It was formerly held that consumption is a hereditary disease. But we know now it is practically impossible for such to be the case, for parents can not transmit the bacillus to their offspring. What parents may transmit is a tendency to the disease, resulting from unhealthful conditions in their own organisms. Such hereditary transmission may be manifested by the offspring in the scrofulous temperament. The child may have a pallid skin and flabby flesh; and inflammation of the mucous membranes, as would be indicated by reddened and suffused eyelids, coryza and congested and unhealthy throats. There would be adenoid growths in the back of the nose and enlarged tonsils, so that such children would be mouth breathers, starved for oxygen. The glands of the neck and in other parts of the body would become enlarged. Besides these things, there might be malformations of the thorax and a capacity for breathing evidently below the average, congenital affection of the heart and the rest of the circulatory system, slow teething and deficient and tardy ossification. There would, in short, be evidence of defective development and of a generally torpid condition of the system.