THE TESTICLE AND THE OVARY 335 



plumage and the suppression of the racial " henny " characteristics. 1 

 In such strains Boring 2 found that cells resembling the luteal cells 

 of the mammalian ovary were present in the testes, but that they 

 were absent in normal adult cock birds. It was concluded, therefore, 

 that castrating the Sebright produces its effect by the removal of 

 these luteal cells which were held to be responsible for the suppres- 

 sion of cock-feathering. Pease, 3 however, has been unable to find 

 any distinction between normal and henny-feathered cocks in the 

 matter of testicular luteal cells. In the testes of immature birds or 

 birds in which spermatogenesis was only beginning, luteal cells could 

 always be found in both normal and hen-feathered, but in testes 

 showing active spermatogenesis no luteal cells were seen. Pease, 

 therefore, is disposed to believe that Morgan and Boring are not 

 justified in associating luteal cells with hen feathering, and suggests 



FIG. 82. Successive stages in the regression of the comb of the cock after 

 castration : (a) at the time *bf castration ; (b) five weeks after ; (c) seven 

 weeks after ; (d) when regression was complete. (From Pezard.) 



t 



that they may be a source of food for the sperms which are in process 

 of formation. Boring and Pease both found luteal cells in the ovary of 

 the female. Boring had previously arrived at the conclusion that there 

 are no " interstitial cells in the testes of the domesticated chicken in 



1 This observation has been confirmed by the present writer working in 

 conjunction with Professor B. 0. Punnett. It was found further that after 

 the removal of one testis only in hen-feathered cocks, " cocky " feathering may 

 develop on the operated side of the bird. This result may have been due 

 to injury to sympathetic nerve ganglia. Punnett suggests, however, that in 

 one bird it may have been a case of premature development of such feathering, 

 which in the non-occurrence of an operation would have grown at the next 

 moult, since hen -feathered cocks sometimes do subsequently develop an inter- 

 mediate type of feathering. (See Punnett and Bailey, "Genetic Studies in 

 Poultry," III., Jour, of Genetics, vol. xi., 1921. Cf. Bond, "On a Case of 

 Unilateral Development of Secondary Male Characters in a Pheasant, etc.," 

 Jour, of Genetics, vol. iii., 1914.) 



2 Boring, "The Interstitial Cells and the supposed Internal Secretion of 

 the Chicken Testis," Biol. Bull., vol. xxiii., 1912 ; "Sex Studies," Jour, of Exp. 

 Zool., vol. xxv., 1918. See also Boring and Pearl, "Sex Studies," A not. Record, 

 vol. xiii., 1917 ; and Boring and Morgan, "Luteal Cells and Hen-Feathering^" 

 Jour, of Gen. Pkys., vol. i., 1918. 



3 Pease, "Note on Professor T. H. Morgan's Theory of Hen Feathering," 

 Proc. Camb. Phil. Soc., vol. xxi., 1922. 



