56Section I.R. Pearl.
From the data set forth in the above table there can be no doubt as to the
fact of the Mendelian segregation of fecundity, nor as to the entire
distinctness of the things segregated.
In order to give a general survey of the results, and to demonstrate
the reality of segregation over the wide range of material included in the
experiments, the summary Table III. is presented.
Table III.
Showing the Observed and Expected Distributions in Res feet of Fecundity
of the Adult Female Offspring from all Matings in each of the Classes
Tested in the experiments.
Winter Production of Daughters.
Class.Over 30.Under 30.Zero.
All Barred Plymouth Rock xObserved3654259431
Barred Ply. RockExpected38*'45257'2517-30
All Cornish Ind. Game x CornishObserved22315
Ind. GameExpected025*5
All F1 (B. P. R. x C. I. G. andObserved36798
reciprocal cross)Expected26586-759-75
All F2 (Fx x F15 and Fj x parentObserved57498423
forms in all possible com
binations)Expected68 6095'0015 '40
Considering the nature of the material and the character dealt with the
agreement shown between observation and hypothesis is certainly as close
as could reasonably be expected. Such discrepancies as are shown in the
above table are fully discussed and their probable physiological explanations
set forth in detail in the complete account of these experiments.
The detailed data given in the complete paper, of which the above
discussion and tables give merely a very incomplete abstract, appear
definitely to establish the following points:—
1. That fecundity, in the domestic fowl, is inherited strictly in
accordance with Mendelian principles.
2. That observed individual variations in fecundity here depend upon
two separately inherited physiological factors, Lx and L2.
3. That high fecundity is manifested only when both of these factors
are present together in the same individual.
