THE AMERICAN NATURALIST [Vol. XLIX 



3. Selection as breeders of males whose dams had laid 



more than another definite number of eggs (200). 



4. The indiscriminate mass breeding, without individ- 



ual pedigrees, of all individuals selected as de- 

 scribed under 2 and 3, and, in consequence, 



5. No test of the progeny of particular matings with 



respect to their laying ability. 



This may be designated as the period of mass selection. 



The following statement regarding the methods used 

 in this period was made by Woods and Gowell {loc. cit., 

 p. 8): 



The plans followed in this breeding work are based upon everyday, 

 practical common sense, and are tlie same as would be used in building 

 up a high-producing strain of dairy animals. Individual records of 

 performance are kept. The large producers are mated with sons of 

 large producers in the hope of obtaining a race of improved layers. In 

 the first year's work three birds laid over 200 eggs each, and this fact 

 led to the adoption of that number of eggs as the minimum perform- 

 ance for a "registered" bird. Other than this there was no reason for 

 selecting 200 as the number of eggs necessary to entitle a bird to regis- 

 tration. Any other number, as 190 or 210, might have been taken with 

 equal propriety, just as horsemen might have selected some other time 

 than 2.30 by which to determine a standard horse. 



2. The Period from 1908 to 1912.— For reasons which 

 have been fully set forth elsewhere 3 it was decided not to 

 continue the breeding 1 along the same plan after 1907. 

 The new plant, put into operation first in the breeding 

 season of 1908, was calculated primarily to furnish defi- 

 nite information regarding the mode of inheritance of the 

 character winter egg production. It involved essentially 

 the following items : 



1. Trap-nest record of the performance of each indi- 



vidual female. 



2. The selection of both males and females was made 



on a double basis, including in addition to the 

 individual's own performance as in the earlier 

 plan, also the idea of progeny performance. In 

 practice this worked out for hens in the following 

 way: Plans were made to see whether there could 



« Pearl and Surface, loc. cit. 



