150 ESSAYS OF A BIOLOGIST 



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 fer 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 

 physical abnormality, this will react upon the mental ; 

 but in the vast majority of cases the physical variation 

 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 

 instinct 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 

 which the analytical psychologists have opened up 



