50 Genetic Studies in Poultry 



made, and when examined in Feb. 1917 it was found that two of them, 

 104 and 276, were putting up some feathers of the cock-like inter- 

 mediate type. Further, these feathers were ahnost entirely confined to 

 the right side of the body, i.e. the side on which the operation took 

 place. The third bird, (/* 78, remained henny. The left testis in each 

 iDird rernained intact throughout. Of the two birds which put up inter- 

 mediate feathers, one ((/ 276) was killed in July 1917 in order to 

 preserve the skin as a record. The other was kept over another moult, 

 and, having become fully henny again, was killed on March 3, 1918. 

 The explanation of this peculiar phenomenon is obscure. It is clear 

 that a local lesion may influence the character of the feathering on 

 the side on which it occurs, although the hormone must be supposed 

 to be circulating equally on both sides. It seemed conceivable that 

 injury to the sympathetic nervous system rnay have been concerned, 

 for it is so closely in contact with the genital gland that it is impossible 

 to remove the latter without nervous damage. We think however that, 

 in the light of some subsequent experiments by Dr Marshall, another 

 explanation is possible. 



Dr Marshall removed the right testis in three birds hatched in 1919, 

 the operation being performed in November. Two of these birds (t/ 337 

 and (^ 400) were almost fully henny in their first plumage, and remained 

 so after their moult in 1920. In neither case did they put up any 

 intermediate feathers on the side on which the operation took place. 

 The third bird ((/ 346) was intermediate in the character of the 

 feathering. In March 1920 he shewed a well-marked patch of full 

 henny laced feathers on the fore part of the right saddle, i.e. in the 

 position in which most of the intermediate feathers appeared in 

 cf 104 and ^^ 276. The relatively sharp lacing and paler ground of 

 these henny feathers made the patch shew up conspicuously against 

 the more warmly tinted intermediate feathers. Later on in the year 

 this bird moulted out practically full henny, the feathers on both sides 

 being similar to those found on the patch that appeared earlier on the 

 right side. Whatever the reason, the operation seems to have caused 

 an earlier appearance on the right side of feathers which would normally 

 have developed at the next moult. We know that henny birds may 

 subsequently develop an intermediate type of feathering (p. 42). It 

 seems just possible that cT 276 may have been such a bird, and that 

 the operation led to a premature development of intermediate feathers 

 because he would have developed such feathers at his next moult had 

 he not been killed. On the other hand, (/* 104 was allowed to live and 



