“... in round figures a quarter of our insane patients show more or less clearly extensive changes and destruction of the brain, while three-fourths have a brain which seems to be generally unimpaired or at most exhibits such changes as give no explanation of the psychological disturbance.... We must take into account the fact that those mental diseases which show the most marked disturbances of the brain end in death; for this reason the chronic inmates of the asylum form its real population, and among them are some 70 to 80 per cent. of cases of dementia præcox, that is of patients in whom anatomical changes are practically non-existent.”[57] In a great number of mental disorders our present knowledge of anatomy, physiology and pathology is of little help as a means of throwing any light upon the patient’s condition. While in no way attempting to belittle the magnificent work in these subjects during the past century, it should be pointed out that its very success has brought about, especially in this country, an unfortunate tendency to regard these methods as the only ones suitable for attacking the problems of insanity. But nothing is more certain than that in the psychoneuroses: hysteria, neurasthenia, psychasthenia and the rest, anatomical and physiological knowledge has not yet passed beyond the theoretical stage[58]. But it is equally indisputable—and the statistics of shell-shock cases have strengthened the evidence for this assertion—that the psychological mode of attack, the treatment of mental disorder by mental means, is now firmly established as a practical method. It appears, therefore, that precisely in those cases of psychoneurosis which yield to psychical treatment, there is no anatomical, pathological or chemical evidence of inheritance.