178 Sex- Reversal in Frogs and Toads 



A difficulty naturally arises. If the above be true, then there is 

 reason to question the accepted statement that Bidder's organ is a rudi- 

 mentary ovary. This organ persists in the male but disappears in the 

 female, which suggests that it is spermatic rather than ovarian in nature, 

 but so deficient in interstitial tissue that the hormone of the ovary, 

 becoming exhibited in the absence of the hormone of the spermatic 

 tissues, produces its ultimate destruction. In this connection, it will be 

 remembered that Cerruti found spermatozoa actually within a Bidder's 

 organ and that Hoffmann described rudimentary seminal tubules 

 therein, whilst the experimental work of Harms supports the idea that 

 Bidder's organ is male in nature. 



Harms maintains that Bidder's organ is an organ of internal secre- 

 tion and has conducted experiments which show that the development 

 of the typical male finger-pads is controlled in some part by this organ, 

 for, while extirpation of the testis or of Bidder's organ has no influence 

 upon the development of the pads, yet if, after extirpation of both testes 

 and Bidder's organs, a Bidder's organ is grafted in the dorsal lymph- 

 sacs, the typical seasonal development of the pigmented pads follows in 

 due course. 



Goldschmidt has shown that Bidder's organ undergoes changes which 

 are parallel to the sexual cycle and that in the case of the male there is 

 increased activity and regeneration of its constituent cells, co-incident 

 with the formation of the spermatozoa. 



Cytologically it has not been proved that the cells which constitute 

 Bidder's organ are ovarian, and there undoubtedly are reasons for 

 questioning the generally accepted opinion that this organ is a rudi- 

 mentary ovary. 



Summary. 



1. It is shown that the recorded cases of abnormality of the repro- 

 ductive system illustrate the process by which an individual, at one 

 time possessing solely the complete sex-equipment of the female, comes 

 to exhibit the organisation of the male. The sole female character which 

 remains in what otherwise appears to be a typical male may be the full 

 development of the Miillerian ducts, or the presence of ova amid the 

 spermatic tissues. 



2. Such a transformed individual not only has the male organisation 

 but also behaves and functions as a male. 



3. It so happened that a transformed individual, functioning as a 

 male, fertilised the eggs of a normal female. This male was one of an 



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