Having reached this first certainty, our psychiatric interest will have become aroused. If we cannot do away with a delusion by taking reality into account, it can hardly have arisen from reality. But the delusion, what is its origin? There are delusions of the most widely varied content. Why is it that in our case the content should be jealousy? In what types of persons are obsessions liable to occur, and, in particular, obsessions of jealousy? We would like to turn to the psychiatrist with such questions, but here he leaves us in the lurch. There is only one of our queries which he heeds. He will examine the family history of this woman and _perhaps_ will give us the answer: "The people who develop obsessions are those in whose families similar and other psychic disturbances have repeatedly occurred." In other words, if this lady develops an obsession she does so because she was predisposed to it by reason of her heredity. That is certainly something, but is it all that we want to know? Is it all that was effective in causing this breakdown? Shall we be content to assume that it is immaterial, accidental and inexplicable why the obsession of jealousy develops rather than any other? And may we also accept this sentence about the dominance of the influence of heredity in its negative meaning, that is, that no matter what experiences came to this human being she was predestined to develop some kind of obsession? You will want to know why scientific psychiatry will give no further explanation. And I reply, "He is a rascal who gives more than he owns." The psychiatrist does not know of any path that leads him further in the explanation of such a case. He must content himself with the diagnosis and a prognosis which, despite a wealth of experience, is uncertain.