Punnett's book on Mendelism contains a sentence which may be applied in many different fields of research: 'By this respect for the individuality of the different plants, however closely they resembled one another, Mendel found the clue that had eluded the efforts of all his predecessors'. Freud has rendered a similar service to psychology—and by the same method; he respects the individuality of the patient's symptoms, of his dreams, of his every act, and has found a clue that no psychologist can afford to neglect. And so we find in Mendelian literature that constant reference to observation and experiment which we claim with pride is the character of Freudian literature also.

The book before us stands out as an example of the opposite method of work and we cannot help regretting that such a carefully written book should spare as an average only one or two words per page to case histories. It is the more incumbent on the author to produce the material of close observation when he presents us with such novel ideas as the following: