SEXUAL HORMONES AND MORPHOGENESIS 447 



sex differentiation. We find the same misunderstanding in a 

 paper by de la Vaulx (1922). 



The view taken by Harms (1922, p. 212) is a contradictory 

 one. He says: "The fertihzed e^^ is sexually determined only 

 in respect of the gonad, whereas the sex characters have an 

 indifferent bisexual anlage. This assumption is widely sup- 

 ported by recent experimental investigation." Now one 

 might suppose that this sentence implies the acceptance in 

 some form of our hypothesis. But on the contrary: "This is 

 why the hypothesis of Lipschiitz on the asexual embryonic 

 form held also by Tandler and Gross, Steinach and Biedl must 

 be rejected, at least for the living animals of to-day." But on 

 p. 216 of the same paper Harms is less radical in his rejection 

 of this hypothesis. Here he merely argues that the sex 

 characters may become differentiated to a certain degree even 

 in the absence of the sex glands, though in the presence of the 

 glands all the sex characters are indifferent before a differentia- 

 tion of the gonad has taken place. 



There is, however, another set of facts which might be cited 

 in opposition to our h5^othesis ; the statements made as to the 

 sex chromosomes. If the number of chromosomes in males 

 and females is different in birds and'mammals, the soma of both 

 sexes must be a different one from the beginning. As far as I 

 understand it, the problem of the sex chromosomes is not yet 

 solved for birds {Goldschmidt, 1920, p. 57). As to mammals, a 

 recent statement of Wodsedalek (1920, quoted from Arch. f. 

 Zellforschung 16, p. 439) may be mentioned. This author 

 examined various embryonic organs such as brain, lung, liver, 

 etc., in cattle, and he records having found in male embryos 

 37 chromosomes and in females 38. It is possible, according 

 to this author, to state the sex of the embryo by counting the 

 chromosomes before the sex can be recognized morphologically. 

 It is clear that our hypothesis, which postulates an identity ol 

 male and female somatic cells before differentiation of sex 

 endocrine cells has taken place, is contrary to the theory of the 

 sex chromosome. If the latter holds for birds and mammals, 

 our theory must fail, at least in its extreme form. But it 

 nevertheless remains true that the male and female soma can be 

 changed in the direction of its development by the influence 

 of an hormonic or some other factor; absence of identity does 

 not exclude "equipotentiality, " to use Zawadowsky's expression. 



2F 



