PREVENTION OF MENTAL DISEASES 73
the hereditary traits presented by the families intrusted to his care ; but it is still more important that men should be taught to know themselves, to know especially the defective factors of their nature, and particularly those which tend to cause decay of their mental faculties and may be transmitted to their offspring. But these principles will remain unknown, or without practical effects, so long as the states do not take to heart the cause of improving their inhabitants, and do not employ radical measures to extirpate all which works toward the intellectual and moral degradation of the people. It is in combating the hereditary forces that the states are to attain the solution of the greater part of the problem which weighs upon them. Very often, in fact, if observation is inadequate, one is inclined to reduce the causes of mental troubles to physical diseases, cerebral disturbances, advanced age, etc. But when we pene- trate the life of the insane or degenerate more deeply by retracing the line of descent, we receive new light. Thus we may come to learn the constitution and temperament of the parents, and if this examination of the children is accurately made, we can make a prognosis and suggest preventive meas- ures. In the same way we can make known to parents the directions which should be followed by teachers and physicians. In fact, only too often the parents refuse to believe that there is any hereditary defect in them, and in such cases it is much bet- ter to ameliorate their offspring without their knowledge.
It is not merely when the parents or grandparents have been afflicted with a mental disease that we have heredity. Other nervous diseases, as chorea, hysteria, epilepsy, hypochondria, neurasthenia, or even merely a nervous state more or less pro- nounced, may introduce a diminished resistance in the cerebral forces and disturb these at the least occasion of injury which may be encountered later in the course of life. The maladies which attack the organism profoundly have generally for cause the debilitation of the nervous system, and this debilitation increases in the offspring if both parents have any serious defect. Pulmonary tuberculosis, gout, cancer, scrofula, or a nervous affection with one of the parents, predisposes to mental
