RELATING TO SECONDARY SEXUAL CHARACTERS. 37 



interstitial cells begin to increase just before the mating season, and 

 the increase continues for several months after mating has taken place. 

 It is difficult to judge how great or how little the change amounts to 

 unless the whole organ is considered, for the relative volumes of the 

 seminal tubes and the interstitial tissues does not give a measure of the 

 total volume of these tissues, since the testes may decrease greatly 

 in size when the seminal tubes retrograde, and the apparent increase 

 of the interstitial cells at the tune may not increase the total amount 

 of that tissue present. 



Probably more important than the ratio of interstitial tissue to 

 tubules is the activity of the former. Rasmussan states that in the 

 woodchuck the interstitial cells not only increase in number immedi- 

 ately after hibernation, but the increase in amount of this tissue is 

 largely due to increase in the cytoplasm, in which there appears an 

 accumulation of fatty globules in the more peripheral parts of the cells. 

 In the central cytoplasm an abundance of fine lipoid granules develops. 



Marshall has made some interesting experiments on the hedgehog 

 at different seasons. Castration in March prior to the breeding- 

 season has an influence on the accessory generative organs (vesiculse 

 seminales, prostates, and Cowper's glands). They remain in the same 

 undeveloped stage in which they were at the time of operation. If 

 castration is carried out very early in the breeding-season, when the 

 accessory reproductive organs are about half developed, their further 

 enlargement is prevented. In so far as the accessory organs rank as 

 secondary sexual organs, their complete development is thus shown 

 to depend on the testes. Transection of the vasa deferentia before the 

 beginning of the breeding-season affects somewhat the enlargement of 

 the testes, but produces no effect on the accessory organs. 



HERMAPHRODITISM IN POULTRY AND THE SECONDARY SEXUAL 

 CHARACTERS. 



Several hermaphrodite birds have been described (Brandt, 1889; 

 Shattock and Seligman, 1906; Pearl and Curtis, 1909; Smith and 

 Thomas, 1913; Bond, 1914; etc.). The most recent and complete 

 account of such birds is that bylBoring and Pearl. They examined in 

 all 8 hermaphrodites, or at least 8 birds that showed in their plumage, 

 or other secondary sexual characters, peculiarities of both sexes. Five 

 of the birds came from Herr Houwink in Meppel, Holland, who had a 

 stock in which there appeared, in 1911, two hermaphrodites out of 80 

 birds, and in 1912, three out of 80 birds. These were the birds studied 

 by Boring and Pearl. In addition, when Pearl saw Herr Houwink's 

 birds in 1910, " there were then on hand a considerable number of these 

 supposed hermaphrodite birds." An anatomical study of the Holland 

 birds showed that one of them was nearly a normal female; three, the 



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