Page:Popular Science Monthly Volume 47.djvu/403

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MORBID HEREDITY.
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generation, 1893) has endeavored to demonstrate the constancy of these associations in a special category of artists and literary men whose imagination seems to rejoice in its departure from common ideas. He is liable to criticism for not having comprehended that the madness of these supposed degenerates consisted simply in seeking to surprise or scandalize, and that at bottom their thoughts were not much different from those of their contemporaries. While this criticism may be just as to M. Nordau, it can not clear the authors concerned from the suspicion of insanity.

Civilization favors the production of exceptional beings, men of genius as well as those most degraded by vice or by mental perturbations. The most civilized nations are as much distinguished by the number of their insane and criminals as by that of their men of talent. Civilization produces variation or excites the tendency to it, and it is manifested chiefly in the masculine sex. The parallel development of insanity, genius, and crime constitutes one of the most interesting illustrations of the tendency to variation which characterizes the evolution of mankind, and which results in a progressive inequality, against which the restrictive laws of individualism are of no avail.

Psychical disorders are often associated in families and individuals with other diseases of the nervous system, either growing out of lesions or not connected with known lesions—nervous affections. The relative frequency or nervous manifestations, whether isolated or associated with nervous or other diseases which we shall consider, is so predominant that all such family morbid manifestations may be designated under the name of neuropathic family.

Nervous diseases may be hereditary, and pass directly from father to son; examples of such are locomotor ataxy, epilepsy, and hysteria; but indirect and dissimilar heredity, as in psychopathies, is more usually observed. Family connections between diseases from lesions of the nervous system and nervous affections are proved by frequent coincidences among relatives, and also by their manifestations in the same person, either at the same time or in different periods of his life. Not rarely, further, are mental and neuropathic troubles met with in the history of the same person; and, moreover, a number of diseases are marked by both classes of symptoms.

The already somewhat chaotic picture of morbid heredity would still be incomplete if we omitted to add that among the members of a nervous family we often meet individuals affected with disorders of nutrition—gout, chronic rheumatism, diabetes—quite often hereditary diseases which, as much by their course as by their relationship, deserve the name of nutritional nervous affections. It should be observed further that other diseases, para-