Is there a Cumulative Effect of Selection? 
Data from the Study of Fecundity in the Domestic Fowl), 
By Raymond Pearl, Ph. D. and Frank M. Surface, Ph. D. 
Introduction. 
The purpose of this paper is to present briefly certain results of 
a series of selection experiments?) which has been carried on at the 
Maine Experiment Station with poultry during the past eleven years 
having as its purpose to get data on the question which stands as 
the title of this paper. The specific character which was the object 
of selection in these experiments was “egg production” or fecundity. 
This is a character which is particularly suited to selection studies 
because it is expressed in integral units and on that account it is 
possible to observe with much exactness and precision the effect of 
any selective or other experimental procedures. 
Before undertaking specifically the discussion of our results it 
will be well to review very briefly the history of biological opinion 
regarding the question of whether there is a definitely cumulative 
effect of selection. It has long been held as one of the most 
fundamental principles of practical breeding, both with animals and 
plants, that the surest way in which to bring about improvement in 
a strain was to select for breeding the individuals of superior quality 
Certainly until comparatively recently a great many breeders would 
1) Papers from the Biological Laboratory of the Maine Agricultural Experiment 
Station. Orono, Maine, U.S. A. No. 12. 
2) The detailed report ot the results of these experiments will be found in the 
following publications by the present writers: 
(a) A Biometrical Study of Egg Production in the Domestic Fowl, Part I — 
Variation in Annual Egg Production. Bur. of Animal Industry, U. S. Dept. of 
Agriculture, Bulletin 110, 1909. 
(b) Data on the Inheritance of Fecundity Obtained from the Records of Egg 
Production of the Daughters of ‘‘200-Egg’’ Hens. Maine Agricultural Experiment 
Station Bulletin 166, pp. 49—84, 1909. 
Induktive Abstammungs- und Vererbungslehre, II. 17 
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