I2 4 



Scientific Proceedings (ioo). 



For the first two-month period of the experiment the averages 

 for the two strains coincide. But in the next period there is a 

 divergence, the plus showing a greater reactiveness by a small 

 margin. In successive two-month periods this divergence is in 

 general increased. There are considerable fluctuations in the 

 curves as are indicated by the facts, — that for two two-month 

 periods, nineteen months after the experiment was begun, the 

 minus strain was actually the more reactive of the two; and that 

 during three other later two-month periods the mean for the 

 minus strain approached that for the plus strain. But in general 

 the means indicate increasing divergence in mean reaction time 

 throughout the main portion of the experiment until for the last 

 nine months the mean for the plus strain was just half that for 

 the minus strain and during the last three months it was less than 

 one third that for the minus strain. 



It can be stated with assurance that with this material there 

 is little, if any, relation between vigor and reactiveness to light 

 and that in line 757 the effect of selection was not due to changes 

 in the relative vigor of the two strains. 



70 (1445) 



Exhibit showing the results of selection for a new Buff Race. 



By C. B. Davenport. 



[From the Laboratory for Experimental Evolution, 

 Cold Spring Harbor, N. Y.] 



A self-colored race of poultry was first produced in China 

 about 1,500 years ago. All buff races of poultry have been 

 derived from this Chinese race, the Buff Cochin. An attempt 

 has been made to create a uniform buff race out of the Jungle 

 Fowl. In 1907 a Jungle Fowl was crossed with a White Leghorn. 

 This gave offspring in which the red of the Jungle Fowl appeared 

 on a white ground, the black of the Jungle Fowl being hypostatic 

 to the white. The birds showing largest amount of red were 

 selected for breeding. During the first two years no progress 

 was made but after that more highly colored red males and more 



