PREVEA'TIOM OF MENTAL DISEASES 95
influence of the environment may contribute to modify sensibly tiie nervous system, and to disturb the brain. To cite only one example of the highest order : there are nations which degener- ate because they are subject to the influence of a journalism which looks more to personal interest, or to the interest of a party, than to the general interest, that of the entire community.
The external world is full of enemies who tend without ceas- ing to break down our psychical and moral faculties, as there are foes hidden in our own bodies. The nervous system of man is accessible to a series of injurious causes, and if one part is able to resist with some ease, the other is smitten, and disease ensues. Man must consider the harmful causes that he may prepare himself for the struggle for existence, that he may learn to vanquish the unhappy forces which tend unceasingly to bring him to ruin. We have cited some striking examples when we mentioned alcoholism, undue intellectual labor of children, excessive religious instruction, etc. These exogenous causes may be complicated with endogenous causes which we can name only in a general way ; their full description would require a too great extension of this paper. It must suffice to mention the influence of a series of somatic maladies upon the psychical state.
Among the persons who offer the greatest access to mental maladies it is necessary to mention, in the first place, those whose nervous system suffers from birth or from the time of a sick- ness ; and among the nervous troubles which show the greatest pre- disposition we include neurasthenia, epileps}-, hysteria, chorea, and the tendency to suicide. To this list we must add the people who show constitutional debility or any disease which ends in an exhaustion of physical and nervous force — as tuberculosis, cancer, chloro-anEemia, rachitis, and scurvy. A second category of the predisposed is met in persons whose brain remains incom- pletely developed, as in the morally insane, imbeciles, idiots, and their offspring. A special treatment is required for each disease, as well for physical as for intellectual and moral educa- tion, to provide resistance power against all which may endanger the nervous system. The struggle must be perpetual. For the
