150 ESSAYS OF A BIOLOGIST 



psychological. It is clear, however, that if some 

 abnormal individuals can be cured by implantation, 

 and others are abnormal owing to an early failure of 

 activation, this conception falls to the ground, and 

 the Freudian is robbed of some of his most cherished 

 examples. . 



In any case, the work on animals definitely shows 

 that, unless the mechanism of activation of instinct 

 by gonad secretion has altered between animal and 

 man more than we have any right to postulate a 

 priori, the quality of gonad secretion and the balance 

 of all the endocrines has to be taken into account far 

 more than is done by the average psycho-analyst. 



This, however, is not to say that the genesis of 

 our attitude towards sex, our sexual behaviour, and 

 our general mental organization in so far as modified 

 by sex, is not normally determined for the most part 

 by purely psychological causes. If there is a physi- 

 cal abnormality, this will react upon the mental; 

 but in the vast majority of cases the physical varia- 

 tion will not take the individual beyond the limits of 

 normality, and when the normal physical limits are 

 not exceeded, the wide range of mental variation still 

 observable is to be ascribed to psychological causes. 

 In other words, abnormal sexual behaviour and in- 

 stinct may be due either to physiological or psycho- 

 logical abnormality, and the latter is probably the 

 commoner cause. 



I am not competent to attempt to treat of the vast 

 and complex psychological aspect of the sex-problem 



