The stage of development which now followed, the transition from catharsis to psychoanalysis proper, has been described by me several times already in such detail that I shall find it difficult to bring forward any new facts. The event which formed the opening of this period was Breuer’s retirement from our common work, so that I became sole administrator of his legacy. There had been differences of opinion between us at quite an early stage, but they had not been a ground for our separating. In answering the question of when it is that a mental process becomes pathogenic, that is, when it is that it becomes impossible for it to find a normal discharge, Breuer preferred what might be called a physiological theory: he thought that the processes which could not find normal outcome were such as had originated during unusual, hypnoid, mental states. This opened the further question of the origin of these hypnoid states. I, on the other hand, was inclined to suspect the existence of an interplay of forces and the operation of intentions and purposes such as are to be observed in normal life. Thus it was a case of “Hypnoid Hysteria” versus “Defence Neurosis.” But such differences as this would scarcely have alienated him from the subject if there had not been other factors at work. One of these was undoubtedly that his work as a physician and family doctor took up much of his time and that he could not, like me, devote his whole strength to the work of catharsis. Again, he was affected by the reception which our book had received both in Vienna and in Germany. His self-confidence and powers of resistance were not developed so fully as the rest of his mental organization. When, for instance, the _Studien_ met with a severe rebuff from Strümpell, I was able to laugh at the lack of comprehension which his criticism showed, but Breuer felt hurt and grew discouraged. But what contributed chiefly to his decision was that my own further work led in a direction with which he found it impossible to reconcile himself.