NEUROVOGY Gk. veiipop, neuron, nerve H- -Xoyta, -loqio, account, from Xe-yetv, lc gein, to say). The branch of science concerned with the anatomy, physiology, disorders, and dis eases of the nervous system. Brain functions associated with mentality are somewhat arbitra rily placed in the field of psychology, and their disorders furnish the topics grouped under the head of psychiatry. Neurological conditions are also studied in the lower animals, giving a sub division of the subjeet, comparative neurology. which with embryology furnishes important facts which aid in understanding the human nerv ous apparatus. In the more limited medical sense. embraces a study of the human nervous system, its diseases (except insanities) and their treatment.
Nervous diseases are: first, morbid manifesta tions of demonstrably disturbed nerve elements, and, second, so-called functional disorders in which actual changes in the physical prope•tie.s of the DetVOLIS system 11:1 Ve not yet been discov ered. The latter are commonly calb-d neuroses, and are steadily tending to enter the former cate gory under improved methods of research. in Many nervous diseases heredity is a marked feature and in the aeqnired diseases of the nerv ous system heredity may play a predisposing part.
There is a general and probably well-founded belief that nervous diseases are increasing in frequency. Absolute statements, however, are impossible, as ninny causative conditions are changing and other newly recognized nervous dis eases are being added to the known list. For in stance. the infectious diseases, such as small l,ox, typhoid, diphtheria, and malaria. are all capable of producing organic and functional nerv ous diseases. Their eontrol by preventive medi cine and hygiene correspondingly reduces that liability. Civilization, on the other hand, by conserving the unfit and prolonging the life of the feeble and neurotic,entails additional nervous disturbances and susceptibilities. There can be no doubt that modern urban conditions favor the development of nervous instability and at the same time bring to bear the additional highly competent noxious influenees of vice, part ieularly through alcoholic and drug habit: and venereal diseases. The monotony and hardships of farm
life, however, are also a factor of morbidity and are particularly active among the women so situ ated. Some occupations bear either a direct or predisposing relation to nervous ailments. Writer's cramp and the entire group of occupa tion neuroses of which it is a type show this feature. Workers in metal, especially lead, phos phorus, mercury, arsenic, those subjected to in halation of various gases, and those whose occupa tion tempts them to indulge in liquors, are liable to nervous disorders. IVork entailing exposure to cold or wet or increased atmospheric pressure, and that attended by great mental strain or monotony. furnishes predisposing factors.
The question of heredity in relation to nervous diseases is one of decided importance. The neu rologist is not content to trace the identical nervous disorder in ,ttecessive generations. or to note its appearance in blood relations. lle prop erly concerns himself with all the facts which tend to tarnish a neuropathic liability. This is in dicated with more or less force by the occurrence of any sort of nervous and mental disease in the antecedents of a given individual. An hysterical !Maher may have :10 epileptic (Alibi and an idiotic grandchild. Even a very highly NI" rtmght nervous organization in mother and father may eventuate in unstable children. The transmission of nervous disease may he direct, the identical malady reappearing. or, what is more common, the defect may show itself by transformation into some allied malady. Atavistic tendencies, through which an intermediate generation es capes, are also frequently noted. Tnberenlosis, rheumatism, gout. dialletes, and Bright's disease are commonly found in neurotic families that the association is morbidly significant. All de bilitating diseases and exhausting conditions in parents may be rellected in nervously unstable offspring. Consanguinity in the parents does not operate detrimentally as far as nervous dis eases are concerned, unless, as is often the case, it brings together individuals of neurotic tenden cies, which are naturally intensified in the chil dren.