Instinct in Man. In the Light of Recent Work in Comparative Psychology: By Ronald Fletcher, Ph.D. New York: International Universities Press, Inc., 1957. 348 pp.

This is an abbreviation of the thesis which Dr. Fletcher submitted for his doctorate at the University of London. His objective is to establish in the context of wider sociological theory a reliable basis of instinct in psychology. Without firsthand acquaintance with psychoanalysis he has no qualms about comparing psychoanalytic instinct theories with the established knowledge of animal instinct as studied by the ethologists.

An excellent historical rendering of the early doctrines, from Darwin and Lloyd Morgan through McDougall and Drever, precedes his account of the recent work of the comparative ethologists, mainly Lorenz, Tinbergen, and Thorpe. The concepts of the ethologists have striking psychoanalytic counterparts. The biophysiological approach is explicit in Tinbergen's definition of instinct as 'a hierarchically organized nervous mechanism which is susceptible to certain priming, releasing and directing impulses of internal as well as external origin, and which responds to these impulses by coördinated movements that contribute to the maintenance of the individual and the species'. The ethologists conclude that there is no evidence of a general 'aggressive instinct' among animals.

In an excellent synthesis Fletcher presents a contemporary theory and classification of instincts which is at variance with Freud. He begins with the instincts proper (the primary impulses) having a definite inherited neurophysiological basis, proceeds to the general instinctive tendencies (the ego tendencies), and concludes with the secondary impulses (containing the elements of inhibition and aspiration derived from the superego).

The author assiduously refutes the concept of the death instinct. Ethological evidence is marshaled to undermine Freud's 'necessary postulate'—the special application of Fechner's principle that the function of the nervous system is to reduce to the lowest level excitations reaching it. What Freud sees as instinctual in sadism and aggression, F