278 THE GLANDS REGULATING PERSONALITY 



physiques, physiognomies, abilities and characters. Deviations 

 in endocrine type from that of the original stock, more of one 

 endocrine and less of another, is at the bottom of the phenome- 

 non of variation, basic for the origin of new species as well as 

 the extinction of the old. In short, viewing the internal secre- 

 tions as determinants, by their quantitative variations, of a host 

 of biologic phenomena furnishes a concrete and detailed founda- 

 tion for Darwin's theory of pangenesis. 



Inheritance of Acquired Characters 



Darwin's theory of pangenesis was an attempt to harmonize 

 everything known in his time about heredity. It supposed that 

 the various organs of the body gave off into the blood substances, 

 themselves in miniature, which were taken up by the sex cells, 

 and so became responsible for the development of their mother- 

 organ in the newly forming individual. Modern knowledge can- 

 not accept all this as a whole. But in a modified version, it has 

 become the germ of a theory of heredity of which J. T. Cunning- 

 ham, of Oxford, is the chief backer. 



Beginning with the traits and qualities which distinguish the 

 sexes, grouped as the secondary sex characters, he showed that 

 they are correlated with the special sexual function of the species 

 in which they occur. These traits appear only when the hor- 

 mones occur which are present in one sex and that only when 

 the gonads of that sex are mature. In some cases they app 

 only at the period of the year when reproduction takes pi 

 disappearing again after the breeding season. Their presence 

 makes certain cells develop in excessive numbers at a particular 

 spot in the organism (as in the growth of 1 from a I 



sweat glands) or causes them to specialise (to make hair on the 

 face in man, or to grow antlers on the head of a stag). After 

 castration, the hormones being absent) all these points of o< 

 trast between the sexes fail to appear. So by anal' 



■lain all somatic and psychic differentiation as functions of 



the glands of internal secretion. Contemplated from the angk 



the effect of environment upon the endocrines, and a r< 



'in upon the germ oells, we may out line a mechanism of 

 ace of acquired char rtain times and o 



sequent adaptation. would be as follows: 



1. A state of lability of cells at a pofall of in- 



creased or decreased use. 



