470 INTERNAL SECRETIONS 



masculinization of a gonad which began originally to develop 

 in the female direction. Finally, the experiments of Minoura 

 (1921) have shown that by cross-grafting the sex of the gonad 

 can be changed in the direction of the sex of the graft. In view 

 of these results it is not impossible that there are hormonic 

 factors in the sex gland which may influence the generative 

 part of the gonad in a sex specific manner. We know of 

 similar influences arising from other endocrine glands such as 

 the thyroid and the hypophysis, which in a general way are 

 connected with metabolic changes in the gonad. These latter 

 influences are, indeed, not sex specific like those of the hormones 

 produced by the ovary and the testicle. But it is not im- 

 possible, however, that the adrenals may exert a sex specific 

 influence on the gonad. One cannot say how far these 

 hormones really interfere with the normal development of 

 the gonad, neither can we draw from the experiments of 

 Minoura any conclusions as to what normally goes on in the 

 gonad, or whether there is really a causal dependence on the 

 part of the generative portion of the gonad upon sex specific 

 hormones. But the question deserves further consideration. 

 Originally I thought it advisable to speak of an asexual 

 embryonic form instead of an asexual embryonic soma, leaving 

 the question open as to whether the generative cells also may be 

 of the nature of sex characters dependent upon sex specific 

 hormones. But to avoid misunderstanding, I prefer to speak 

 of an asexual embryonic soma. 



Kammerer (1919, pp. 343 and 344) has adopted the above 

 genetic system, but proposes to replace the expression " evolved 

 characters of the asexual form" by "characters of the neutral 

 form of the species." 



A similar genetic system has been adopted by Zawadowsky 

 (1922, p. 207). Later on, however, this author (1923, p. 103) 

 has somewhat modified the system in question, and added 

 certain other terms such as "sex-hmited" and "somato- 

 sexual" characters. By "sex-limited" characters he means 

 certain characters of the neutral form occurring in hybrids 

 which are absent in the neutral form of the opposite sex, 

 the soma of the males and females in such cases not being 

 equipotential (see p. 461). By " somatosexual " characters 

 Zawadowsky understands those which are present from the 

 beginning in the soma, and do not depend upon sex hormones, 



