62 THE CAUSATION OF DISEASE. 



transmitted along one sex only.* The potentialities are evi- 

 dently kept in abeyance by some restraining influence, upon 

 the removal of which they are ever ready to spring into exist- 

 ence. 



If we are not careful to bear in mind that a character may 

 pass potentially through one sex, we shall have some difficulty 

 in comprehending aright the doctrine of sexual heredity, and 

 apparent exceptions will frequently meet us. It is often said, 

 for instance, that certain peculiarities pass — not from father to 

 son, or from mother to daughter — but from father to daughter, 

 and from mother to son. Take the case of intellectual capacity : 

 it is vulgarly thought that this passes from the mother to the 

 son rather than from the father. Doubtless, mental ability 

 often comes through the mother, just as gout may, and sundry 

 other characters ; but it may also come from the father's 

 side. 



Indeed, this very instance of hereditary ability illustrates 

 and strengthens the doctrine of sexual heredity. Through 

 untold ages the mental E of the two sexes has differed. The" 

 man has had to use his brain the most, and it has been the 

 fashion to stifle the intellectuality of the woman ; there are, 

 indeed, many men now-a-days who regard an intellectual 

 woman with aversion. Hence, the smaller head of the woman 

 — I speak of averages — and correspondingly smaller mental 

 capacity. The old-fashioned plan of dwarfing the woman's 



* In the " Proceedings of the Zoological Society," December 1886, Mr. Bland 

 Sutton advances an hypothesis to account for this latency of male sexual 

 characters in the female. He alludes to the fact that the secondary sexual 

 characters are chiefly in connection with the skin, and this, no doubt, in the 

 case of many lower animals, is in a large measure correct. Now, the skin is 

 developed from the epiblast, and in Mr, Sutton's opinion, founded on observa- 

 tion, the epiblast is chiefly derived from the male element, the hypoblast and 

 greater part of the mesoblast from the female. The non-development of those 

 male (epiblastic) sexual characters in the female is due, according to Mr. 

 Sutton, to the large demands made upon the rest of the economy, by the female 

 generative system. This hypothesis affords no explanation of the larger and 

 more comprehensive problem, " What determines the sexes ? " nor does it 

 explain how non-sexual characters— altogether independent of the epiblast — 

 such, for instance, as the deformities I have alluded to, may pass along one 

 sex only. This latter fact alone is strong evidence against the tenability of 

 his hypothesis. It, moreover, takes no account of the fact, that the male 

 contains the potentialities of the female. 



