192 CARL G. HARTMAN AND WILLIAM F. HAMILTON 



functional cytology of the fowl testis, it is idle to apply the term 

 'normal' to these specimens. There may be cited, further, the 

 obscure and disconcerting gynandromorphs described by Weber 

 ('90), Poll ('11), and Bond ('13). Nevertheless, a consideration 

 of all the facts force us to take the contrary view to that proposed 

 by Boring and Pearl; for if the internal secretion of the testis be 

 denied, the sex characters of the hermaphroditic birds listed 

 in table 1 would have to be explained simply on the basis of the 

 degeneration of ovaries (cf. Morgan, '19, p. 39). We believe 

 this explanation to be inadequate for the following reasons: 



First, if the three cases of gynandromorphism cited above 

 are invoked against the internal secretion of the testis, the in- 

 ternal secretion of the ovary must also be denied. 



Second, while degeneration of the ovaries of zygotic females 

 is correlated with the assumption of male plumage, such male- 

 feathered females have atrophic, capon-like combs and wattles 

 but the hermaphrodites have almost invariably cock's combs 

 and wattles associated with hen feathering. 



Third, capons possess mere rudimentary (not female) combs 

 and wattles; but regeneration of incompletely extirpated testes 

 (Bond, '13), transplantation of testes into capons (Bernard, 

 '49), injection of testicular extract, even of mammalian testes 

 (Pezard, '11, '18, '21a; Loewy, '03) — all result in a resumption 

 of growth of head furnishings. Experimental evidence of this 

 character is usually considered conclusive with reference to any 

 other endocrine organ (Biedl, '13). 



Fourth, Pezard ('18) was able to cause growth to comb and 

 wattles in an ovariotomized pullet by successfully engrafting 

 testicular tissue, which is quite in accord with Steinach's results 

 of heterosexual transplantation of gonads and the production of 

 hermaphrodites in mammals. 



Fifth, if it is urged that nos. 1429, 1428, 1427, and 1425 of 

 table 1 are females which exhibit hermaphroditic tendencies 

 simply because of the presence of degenerating ovaries, we would 

 answer with the well-known fact that the presence of germ cells 

 is no criterion of the endocrine activity of the gonad. ^ Further- 



* Compare Pearl and Curtis ('09) and various vasectomy experiments on 

 mammals (Steinach, etc.). 



