Page:Popular Science Monthly Volume 78.djvu/23

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die of that disease. No, the causes of death as given in the health reports or census bulletins are not the real causes. All of these results are due to an inciting condition acting on a susceptible protoplasm. The real cause of death of any person is his inability to cope with the disease germ or other untoward condition.

The fact that of all occupations of females that of servant shows the highest death rate from consumption does not imply that this occupation is extra-hazardous to the lungs or to body-resistance rather than that servants are largely Irish (who as a nation lack resistance to tuberculosis) or that they are below the average in mental and physical development, including disease resistance.

What is true of consumption is true of various diseases that are commonly thought not to be due to germs, but to conditions of life. Insanity is one of these. Mr. A. goes insane; we explain that it is because of business losses or overwork. But there are a lot of us who have severe losses or who work hard and show no signs of nervous breakdown. It would be more accurate to say A. went insane because his nervous machine was not strong enough to stand the work put upon it. Insanity (except perhaps paresis and the so-called "alcoholic psychoses") rarely occurs except where the protoplasm is defective. Also epilepsy, which is so often ascribed to external conditions, is, like imbecility, determined chiefly by the conditions of the germ plasm; and the trivial circumstance that first reveals the defect is as little the true cause of the defect as the touching of the button that opens an exposition is the motive power of the vast engines.

The variations of density in the geographic distribution of a disease, upon which climatologists lay so much stress, does not always warrant the popular interpretation of the facts. A heavy incidence of disease in any county does not always mean unfavorable environment. I have plotted the distribution of imbeciles received by an institution in a small state. The ratio of incidence of this condition to the entire population is high in some counties (chiefly rural) and low in others, due to the presence or absence of foci of the defect. Similarly the varying rate of deaf-mutism is determined by the density of defective germ plasm. So, also, despite its fine climate, the rising generation in California is characterized by diseases of the mucous membranes, because a generation ago much weak protoplasm was attracted to this state as a sanatorium. No, blood is as important a factor in determining the occurrence of disease as climate.

Crime, which the euthenist finds so related to conditions, proves to be, like disease, a resultant of conditions and blood. Only so can we explain the pedigree trees of criminal families like the Jukes and the Zeros. Tactful, firm, sympathetic, just treatment can do much to reform juvenile delinquents, but if the moral sense and balance are