SEXUAL HORMONES AND MORPHOGENESIS 465 



female, and of female characters by the male can he explained on 

 the assumption of a transmission of the characters of an asexual 

 soma, which has the capacity to react in a male, or female manner 

 according to the sex specific hormones, the latter being possibly 

 not peculiar to the species. 



In the six years which have elapsed since I wrote the above 

 passage in the first edition, the papers of Morgan, Zawadowsky, 

 Pezard and Caridroit, and that of Cuenot, as reviewed above, 

 have come to my knowledge. In these we see that the view 

 here expressed has proved, quite independently of mine, to 

 be a useful working hypothesis. 



Though I am not trained in the study of genetics, I may be 

 permitted to point out that the number of genetic factors 

 which during the last few years has been multiplied so enorm- 

 ously, may be brought within much more reasonable limits, 

 when a fuller knowledge has been gained concerning the mutual 

 relations between the various groups of cells or organs during 

 the progress of embryonic development. 



G. CLASSIFICATION OF SEX CHARACTERS. 



We shall now attempt to classify the sex characters on the 

 basis of our theory of the sex specifity of the hormones, and 

 the asexuality of an embryonic soma feminized or masculinized 

 thereby {LipschUtz, 19 18 a). The principles of the classification 

 I propose here have been recognized by Pezard {19 15) in 

 discussing his experiments on fowls. 



Two groups of sex characters can be distinguished : — 



(i) Sex characters not dependent upon sex specific hormones. 



{2) Sex characters dependent upon sex specific hormones. 



In regard to the characters not dependent on sex specific 

 hormones, it may be recalled that they can be considered as 

 evolved characters of the asexual soma, which become sex 

 characters only in the sense that they are changed by sex 

 specific hormones in the opposite sex. 



The second group deserves further consideration in detail. 

 The influence of one organ on another is always a quantitative 

 one ; there is a change in the intensity of the metabolism or at 

 some link in the metabolic chain; there is an increase or a 

 decrease in the growth intensity of the cells. So one might 

 assume that the sex specific hormones will act on the characters 



