50 
ZOOLOGY: R. PEARL 
Females: AA = ^'" + ^ thus 4/8, 18/32, 76/128, etc. 
^20 + 1 
Aa = - — ; thus 1/4, 3/16, 9/64, etc. 
aa = ^2a+jJl3^. ti^^s 2/8, 8/32, 34/128, etc. 
Males and females equal in number. 
In all these series the proportions of any given sort gradually approach 
a Hmit; thus in the last case (24) the limit for A— is 2/3; for a—, 1/3; 
for AA it is 2/3; for aa, 1/3; for Aa the limit is 0. 
In the full paper there is a systematic presentation of formulae for 
the proportions in any generation, resulting from any of the main types 
of breeding, and with any of the common types of parental population, 
giving eighty- two numbered sets of formulae. In each case the limit 
approached is given, together with the number of generations of breed- 
ing required to come within 1% of that limit. The complete paper ap- 
pears in the first number of Genetics. 
ON THE EFFECTS OF FEEDING PITUITARY BODY (ANTERIOR 
LOBE) SUBSTANCE, AND CORPUS LUTEUM 
SUBSTANCE TO GROWING CHICKS 
By Raymond Pearl 
BIOLOGICAL LABORATORY. MAINE AGRICULTURAL EXPERIMENT STATION 
Received by the Academy, December 17, 1915 
In connection with the studies of Pearl and Surface^ on the effect of 
pituitary substance on the function of egg production in the domestic 
fowl it seemed desirable to see whether the initial activation of the ovary 
could be accelerated by means of this substance. A pullet of a good 
producing strain hatched at the proper time and well grown will begin 
to lay when from five to six months of age ordinarily. Can such pul- 
lets be brought to sexual activity and laying any earlier if regularly fed 
pituitary substance? 
Forty-five pure-bred Barred Plymouth Rock pullets, all hatched the 
same day (April 29, 1915) were divided into three lots of 15 each. They 
were so chosen that the total weights of the three lots, and thus the aver- 
age weight per bird, were identical at the beginning of the experiment. 
Further great pains were taken to get birds of the same stage of maturity 
and physiological development so far as could be determined. Each 
bird in one lot (A) received per os 0.082 g. per day of pituitary body 
