In 1915 Birnbaum summarized seventy-two articles written on war psychoneuroses in the German army up to the middle of March of that year. On analyzing this study Hoch reached the conclusion that the rate of psychoses was only about two in ten thousand, which would appear to be entirely too low. Birnbaum compared the statistics of various observers showing the frequency of psychoses during the first year of the war as follows:—"Psychopathic constitution, hysteria, traumatic neuroses, etc., Bonhöffer, fifty-four per cent; Meyer, 37.5 per cent; and Hahn forty-three per cent. Alcoholism, acute and chronic, Bonhöffer, ten per cent; Meyer, 21.5 per cent; and Hahn, twenty-one per cent. Dementia praecox, Bonhöffer, seven per cent; Meyer, 7.5 per cent; and Hahn, thirteen per cent. Epilepsy, Bonhöffer, fourteen per cent; Meyer, 11.5 per cent; and Hahn, eight per cent. Manic-depressive insanity, Bonhöffer, three per cent; Meyer, four per cent; and Hahn, two per cent. General paralysis, Bonhöffer, six per cent; Meyer, 3.5 per cent; and Hahn, three per cent." In discussing these findings Hoch says:—"It is clear from this table that psychopathic constitutions, various psychogenic reactions, hysterical and anxiety states, also exhaustive conditions—all of which are included in the first group—are strikingly frequent; whereas the more serious constitutional disorders, such as manic-depressive insanity, dementia praecox and epilepsy are much rarer." Both Birnbaum and Bonhöffer expressed surprise at the infrequency of manic-depressive conditions. Wollenberg found that the individuals who broke down during mobilization, and who had the least resistance, developed manic-depressive insanity, paranoid schizophrenias, episodic psychopathic excitements and occasional clouded states. The cases appearing at the front, on the other hand, were largely hysterias, anxiety states and exhaustive conditions. Birnbaum described psychoses similar to those reported by Awtokratow in the Russo-Japanese war and characterized by great weariness with a tendency to weeping, disturbed sleep and hallucinations related directly to unpleasant war experiences to which the patients had been subjected. He attributed these to exhaustion. Lust[100] quotes Mörchen as finding only five cases of war neuroses in forty thousand prisoners at Darmstadt and found very few cases in an additional twenty thousand which he investigated himself.