INTERNAL SECRETION OF OVARY 273 



next year's cycle are already partly formed, showed an antici- 

 pated regression of the pads. There was also a total lack of the 

 clasp reflex, and the animals were not capable of copulation. 

 The authors conclude from their experiments that the sex 

 characters of the toad do not depend upon the Bidder's organ. 

 They go so far as to suggest that this organ, being a rudi- 

 mentary one, has no function at all ; they consider it 

 as some kind of progonad which stops functioning early, 

 and is to the functional gonad somewhat as the pronephros 

 is to the definite mesonephros in Batrachia. 



The experiments of Lauche (1915) upon partial castration 

 of frogs may also be mentioned here. He removed the greater 

 part of the ovaries in two frogs, and stated that the number 

 of young ova which entered upon development was greatly 

 increased. There was, as he says, an acceleration in the 

 development of ova. He concludes from his experiments 

 that this is caused by an increased demand on the endocrine 

 function of the generative tissue of the ovarian fragment. I 

 do not find that this conclusion is justified. The experiments 

 with partial castration in mammals, which we related above, 

 show that the question is probably a much more complicated 

 one. 



What we know about the seat of hormone-production 

 in the ovary of birds is also very incomplete, although several 

 authors have contributed much to this question in the last five 

 years. Goodale (19 16) observed that castrated hens which had 

 assumed the male plumage reassumed the female one, and 

 afterwards again assumed the male one; Goodale observed 

 six similar hens. One might suppose at first that there was 

 in these cases a regeneration of ovarian tissue left unwittingly 

 in the body; for some this may, indeed, have been so. But 

 on the other hand Goodale states that in certain of his cases 

 there was no trace of ovarian tissue. In these birds he found 

 a new organ which developed in the place of the removed 

 ovary. The histological examination, which was, however, 

 incomplete, revealed that this organ resembled that which is to 

 be found sometimes in normal hens and ducks on the right side 

 in the place corresponding to the left ovary .^ It is impossible 

 to say whether there was any relation between the body on the 



^ It may be remembered that in birds the sexual organs develop only on 

 the left side, whereas they degenerate on the right side. 



