88 a EXPERIMENT STATION. [Jan. 



prolapses of the oviduct and accident or ruptured blood vessels, 

 while the proportion of sickness has been a great deal smaller 

 (practically none), being confined to the few birds that have 

 died. That the isolation has been effective is evidenced by 

 the development of colds in a lot of cockerels about two weeks 

 after they were transferred from the isolated range to the old 

 plant and allowed to mingle freely with the stock there. Other 

 trials yielded similar results. It seems hardly possible that 

 better proof of the effectiveness of isolation in preventing this 

 class of diseases could be obtained without elaborate experi- 

 mentation. 



Work on several phases of the relation of the secondary 

 sexual characters to the gonads has been continued. Some- 

 thing like 8 or 10 cockerels and 4 drakes have been successfully 

 feminized. A series of experiments designed to secure grafts 

 of ovaries into hemicastrated males yielded negative results. 

 In another series of experiments the ovaries were first removed 

 from several Brown Leghorn females, and several weeks after- 

 wards, when the success of the operation seemed assured, as 

 indicated by the persistent growth of male characters, the 

 ovaries from some White Plymouth Rock chicks were implanted 

 on the right side. All the grafts appear to have taken, as in- 

 dicated by the reversion of the plumage to the female form. 

 This type of experiment should yield results along three lines: 

 first, effect of the foreign ovarian secretion on the plumage; 

 second, data on the nature of broodiness, since the ovaries 

 were from a broody race, while the hosts belong to a non- 

 broody race; and third, data on the effect of the soma upon 

 the germ plasm. 



Mr. White began a study of linkage in fowls as his thesis, 

 but abandoned it when he transferred to the department of 

 botany. The results already secured are so promising that the 

 work will be continued. 



