STUDIES IN THE EXPERIMENTAL ANALYSIS OF SEX. 595 



a little larger than the ordinary Bantam. The coniljs in all 

 these birds were similar single combs, but in Nos. 8, 9, and 

 10 the combs were lai'ger, these birds being two years old 

 and having a strain of Silky in them. The other three birds, 

 No&. 5, 6, and 7, were pure Jungle fowls of one year's age. 



No. 5 was injected with 117 c.c. extract in sixty-two days. 

 The increase of the comb was 76 per cent. After the cessa- 

 tion of the injections the comb fluctuated in size, but after 

 having decreased a little it increased again, and five months 

 after the injections had ceased it Avas rather larger in area 

 than ever before. There was therefore no tendency to 

 decrease after the cessation of the injections. Eesult doubtful, 

 perhaps positive. 



No. 6 was kept as a control bird from February 22nd to 

 September 7th, during which period it showed an increase of 

 comb of 29 per cent. It was then injected with 53 c.c. 

 extract in twenty-one days, during which period the comb 

 remained quite constant, showing no increase. Kesult entirely 

 negative. 



No. 7 was kept as a control from AjDril 7th to June 14th, 

 during which period the comb increased 16 per cent. It was 

 then injected with 45 c.c. extract in fifteen days, during which 

 it showed an increase of 35 per cent. The comb decreased 

 again in August, but spontaneously increased 35 per cent, in 

 September without any injections being administered, this 

 increase being the same as that observed while the injections 

 were going on. Subsequently, in November, the comb again 

 increased, bringing up the percentage increase to 78. The 

 result of injection was therefore entirely negative. 



Bird No. 8 was injected with 7H c.c. extract in fifty-two 

 days, during Avhich period the comb inci'eased 14 per cent. 

 Eesult negative. 



Nos. 9 and 10 were kept as controls during the whole 

 period of the injections of the other bii-ds, and they showed 

 percentage increases of 33 and 31, 



The result of this experiment, then, is that in no case was 

 the percentage increase of the comb greater in the injected 



