Those who have given most study to the subject, however, know very well that this conclusion is quite as unjustified by the facts of the case as the corresponding one with regard to religion being a frequent source of nervous diseases. We will discuss that in the chapter on Nervous Diseases, and almost necessarily the closely related subject of mental disturbances is touched on somewhat there. Of course it is well understood that a great many of those who are on the road to such mental alienation {206} as will eventually require their internment in an asylum will give many external manifestations of religious feelings, some of them exaggerated beyond reason, as perhaps the very earliest striking symptom of their mental alienation. Religion, as we said in the Introduction, is one of the most universal interests of men. When people go insane, some interest will receive exaggerated attention. The delusions of their insanity are dependent on what the deepest interest of the individual was. If he was interested in money, he will believe himself the richest or perhaps the poorest of men. If he is interested in science, his delusions will be associated with that subject. Delusions concerning some phase of science are probably even more common in our day than those based on religion. Electricity is the source of more delusions than anything else, though hypnotism and telepathy and other sensationally exploited modes of so-called psychology are a close second in this respect. If the patient has recently suffered a severe loss by the death of a friend, sorrow will be the central idea of his mental disturbance; if there has been a disappointment in love, that will be the focus of his mental troubles; if there has been a money loss, that disappointment will be the core of the depression. Almost any human interest may thus become the root of excitement or discouragement leading to mania or melancholia. The Great War gave us some very interesting material as to mental as well as nervous disease. In nothing was that more interesting than as to the causes from which insanity develops. It might very well have been expected that a great many people would break down under the awful conditions in which they were placed during the war. For instance Poland was fought over some six times, {207} and portions of Austria overrun three times, and Servia was, between war and the ravages of famine and disease, a veritable shambles of its people for three or four years. It is easy to understand the awful states of anxiety and solicitude and almost continuous terror to which the inhabitants of Belgium, occupied by the Germans, were subjected, particularly in the smaller places where they were utterly at the mercy of the German officials whose one idea, fostered by their military teaching, was that the end of the war would be brought about or at least greatly hastened by a policy of frightfulness.