Jaspers (1946) has pointed out that in the history of psychiatry one can distinguish two main types of psychiatrist. On the one hand there is the describer who depicts a lively clear clinical picture and communicates it to the reader in everyday speech. On the other hand there is the analyst who dissects the clinical picture and tries to obtain clear concepts about the abnormal phenomena. The describer is always popular because little effort is required to understand his views and appreciate his clinical descriptions. However it is much more difficult to understand the analyst as this requires time-consuming preparatory work and an attempt to apply the analyst's views in practice. Thus anyone who wishes to understand the views of Kleist and Leonhard, who are the modern representatives of the great clinical analyst Carl Wernicke, has a difficult task. If therefore this present communication appears to disagree with other work recently published by the author (Fish, 1957b, 1958) then all that can be said in extenuation is that the analysis of clinical pictures is difficult and one can only achieve accuracy in this field by learning from mistakes.