highly laborious tasks of almost insuperable difficulty. The morbid ideas, impulses, and actions are not by any means combined in the same proportions in individual types and cases of the obsessional neurosis; on the contrary, the rule is that one or another of these manifestations dominates the picture and gives the disease its name; but what is common to all forms of it is unmistakable enough. This is a mad disease, surely. I don’t think the wildest psychiatric phantasy could have invented anything like it, and if we did not see it every day with our own eyes we could hardly bring ourselves to believe in it. Now do not imagine that you can do anything for such a patient by advising him to distract himself, to pay no attention to these silly ideas, and to do something sensible instead of his nonsensical practices. This is what he would like himself; for he is perfectly aware of his condition, he shares your opinion about his obsessional symptoms, he even volunteers it quite readily. Only he simply cannot help himself; the actions performed in an obsessional condition are supported by a kind of energy which probably has no counterpart in normal mental life. Only one thing is open to him—he can displace and he can exchange; instead of one silly idea he can adopt another of a slightly milder character, from one precaution or prohibition he can proceed to another, instead of one ceremonial rite he can perform another. He can displace his sense of compulsion, but he cannot dispel it. This capacity for displacing all the symptoms, involving radical alteration of their original forms, is a main characteristic of the disease; it is, moreover, striking that in this condition the ‘_opposite-values_’ (_polarities_) pervading mental life appear to be exceptionally sharply differentiated. In addition to compulsions of both positive and negative character, doubt appears in the intellectual sphere, gradually spreading until it gnaws even at what is usually held to be certain. All these things combine to bring about an ever-increasing indecisiveness, loss of energy, and curtailment of freedom; and that although the obsessional neurotic is originally always a person of a very energetic disposition, often highly opinionated, and as a rule intellectually gifted above the average. He has usually attained to an agreeably high standard of ethical development, is over-conscientious, and more than usually correct. You may imagine that it is a sufficiently arduous task to find one’s bearings in this maze of contradictory character-traits and morbid manifestations. At the moment our aim is merely to interpret some symptoms of this disease.