sentences which would be appropriate enough in a medical treatise but which were hardly suited to the larger American and English public whom I hope the book will reach. Figures 9 and 10 of the original did not lend themselves easily to reproduction, and I have substituted two others procured through the kindness of Professor E. L. Thorndike. H. A. A. PREFACE CCORDING to the scientific theory of monism, or the "Identity" hypothesis the only theory, in my opinion, which is consistent with the facts, mind and living brain are one and the same thing. See Forel, Brain and Mind1; The Mental Powers of Ants 2; Monism and Psychology.3 From this it follows that our mental life, and therefore our moral life too, is an expression of our brain life; and for this simple reason all the phenomena of mental life must be considered in any account of nervous or brain hygiene. Questions of social hygiene and of morals are more special. My conception of popular hygiene is that it enables an intelligent layman with a fair education to govern his life in such a way as to avoid diseases and abnormalities as far as possible for himself, his fellowmen, and his offspring, and to promote the health and strength of them all in every respect. Hygiene should in no wise supplant the expert 1 Gehirn und Seele, E. Strauss, pub., Bonn. Die Psychischen Fähigkeiten der Ameisen, E. Reinhardt, pub. Munich. Ants and Some Other Insects, Kegan Paul, pub., London, 1904. "Monismus und Psychologie," Polit.-anthrop. Revue, 1903, physician; and yet it should manage to make the occasions for his assistance as rare as possible. I believe further that rules of hygiene whose grounds are not understood can easily do harm; and with the nervous system and its functions, which are commonly so badly misunderstood, a thorough explanation of the relations involved is on this account especially indispensable. To my dear friend and colleague, Dr. Wolfgang Bach of Zurich, I must offer special thanks for the excellent assistance which he has given me in the revision of this work. A. FOREL. Chigny pres Morges, Vaud, Switzerland, June, 1903. [Preface to second edition, dated Feb. 1905.] |