— 23 —
these effects will disappear. He must learn to regard the memories as part of the furniture of his mind, and as mere traces of events which are past. They must, in fact, be placed in their proper perspective, so that he will finally be able to contemplate them with equanimity. When this has been achieved the internal conflict will have disappeared, and with it the evil consequences which that conflict produces.
We may pause here for a moment and attempt to summarise the facts so far elicited. Throughout the history of medicine very different views have been held with regard to the causation and treatment of mental and nervous disorders. Some of these, "possession," for example, have only an historical interest, but in later years two schools of thought have arisen which still hold the field. One maintains that these disorders are the results of physiological processes occurring in the brain and other organs, and that all attempts at treatment should be directed solely to these processes. The other holds that the disorders are the result of disturbed mental processes, and that corresponding methods of treatment of a psychological order should be adopted. The view outlined in this lecture is that neither of these one-sided conceptions is wholly correct, and that the chain of causation includes in every case both physiological and psychological factors, but that these vary in relative importance very greatly in different types of disorder. In some the physiological factors are all predominant, and in such cases psychological methods of treatment are obviously unsuitable. In others mental factors are equally
