148 CARNEGIE INSTITUTION OF WASHINGTON. 



that produced twins died; possibly because of inability of small 

 yolks to meet the needs of twin embryos. 



The Prediction' of Future Egg Production in the Fowl from its Fecundity 



AT A Particular Time. 



With the development of more intensive agriculture and animal 

 husbandry, there must be an increasing stringency of selection of the 

 individual organisms upon which production depends. For the past 

 several years Dr. Harris, with a number of collaborators, has been 

 working on the problem of the prediction of the future egg-production 

 of the fowl. It is upon the possibility of such prediction that the 

 elimination of poorer birds from the flock, with a consequent increase 

 in average production, depends. In a memoir recently published 

 (Genetics, 6 : 265-309, 1920) he has shown that for a flock as a whole 

 the average annual egg-record may be predicted vv'ith a relatively 

 high degree of accuracy from the egg-production of any individual 

 month. These studies pertain to the records of White Leghorn birds, 

 trap-nested for a period of 7 years at the Storrs International Egg- 

 Laying Contest. Studies on White Leghorn birds at other localities, 

 as well as the fundamental biometric determinations on other breeds, 

 are now under way. 



The foregoing investigations have been limited to first-year pro- 

 duction. The opportunity for an investigation of the relationship 

 between first and second year production is presented by the splendid 

 records of the Vineland Internationl Egg-Laying and Breeding 

 Contest. Dr. Harris is analyzing these data in cooperation with 

 Professor H. R. Lewis, of the New Jersey Agricultural Experiment 

 Station. The results so far obtained show that, contrary to the state- 

 ments of some of the earlier students of poultry genetics, there is a 

 material degree of correlation between the records of the first and the 

 second laying year. Thus, it is possible to extend the practice of 

 culling to the betterment of second-year production. The results 

 show, furthermore, that in the White Leghorn the highest correlation 

 between the yields of individual months are not found in the months 

 of the so-called 'Svinter cycle," but in the autumn months. This is 

 contrary to what would be expected if high annual egg-production 

 were due primarily to a superimposed Mendelian factor for high winter 

 production. A detailed account of a portion of this work is now in 

 press. 



Effect of Alcohol on the Fertility and Growth of Rats. 



Fertility. — In the course of Dr. MacDowell's work with rats and 

 alcohol, data upon fertility and growth have been accumulated. 

 From year to year references have been made to this material as it 

 was being collected (Year Book 1917, p. 116; 1918, p. 113). During 

 the present year all the data on these subjects have been analyzed 



