THE EFFECT UPON HUMAN EVOLUTION 283 



and dwarfs) and abnormal metabolism (goitre, diabetes, and so 

 on) , it has been stated that it would seem that abnormal growth 

 is dominant in the male, and recessive in the female, while abnor- 

 mal metabolism is dominant in the female and recessive in the 

 male. If an endocrine abnormality like a goitre, or cretinism, or 

 a dwarf or giant appear in a family as a sign of endocrine insta- 

 bility, other members of that family will very likely show internal 

 secretion abnormalities. 



If one gland of internal secretion acts as the centre of the 

 system and the others as satellites, we should be able to trace 

 what happens to it in the different generations. Does it main- 

 tain its supremacy? Or will it be ousted by another member of 

 the group? The time will come when we shall thus be able to 

 advise prospective parents of the consequences of procreation 

 and to forecast the meaning for the race of a particular marriage. 

 Internal glandular analysis may become legally compulsory for 

 those about to mate before the end of the present century. 



What are desirable and undesirable matings? The general law 

 followed by nature in her helterskelter way seems to be the pro- 

 duction of the greatest number of hybrids and variations pos- 

 sible, whether for good or evil does not matter. Certain endocrine 

 types appear to be specially attracted to others belonging to the 

 same group. Thus thymus-centered types frequently marry. 

 The ante-pituitary type of male, the strongly masculine, mates 

 often with the post-pituitary type of female, the markedly fem- 

 inine. The children exhibit the lineaments of the pituitary- 

 centered type. The general trend seems to be the establishment 

 of a better balanced, equilibrated type. Yet the children often are 

 apt to segregate into pituitary dominants or pituitary deficients. 

 Happiness and unhappiness in marriage should be examined from 

 the standpoint of endocrine compatibility or incompatibility. 

 Likewise those divorced or about to be divorced. 



The correction of endocrine defects, disturbances, imbalances 

 and instabilities, before mating, presents another field. It re- 

 mains to be seen whether we shall thereby, in one generation, be 

 able to affect at all the germplasm, hitherto revered by all pious 

 biologists as an environment-proof holy of holies. No one can 

 deny, in the face of the multitude of evidence available, that in- 

 ternal secretion disturbances occur in the mother, which, when 

 grave, offer in the infant gross proof of their significance, and 

 therefore when slight must more subtly work upon it. Endocrine 

 disturbances in infancy have been traced to endocrine disturb- 



