706 



THE AMERICAN NATURALIST [Vol. XL VI 



way of summary the following table shows the accord 

 between observation and expectation for all matings of 

 each general type taken together. For reasons set forth 

 below, the lumped figures do not give an altogether fair 

 estimate of the matter, but some sort of a summary is 

 necessary. 



TABLE VII 



All B.P.R. X B.P.R 



f Observed 

 1 Expected 



365| 

 381.45 







All C.I.G. X C.I.G 



All F, 



{IS552 



f i Observed 

 \ Expected 





 36 



79 







f Observed 

 1 Expected 



68.60 



98! 

 95.00 





Considering the nature of the material and the char- 

 acter dealt with it can only be concluded that the agree- 

 ment between observation and hypothesis is as close 

 as could reasonably be expected. The chief point in 

 regard to which there is a discrepancy is in the tendency, 

 particularly noticeable in the B. P. R. X B. P. E. and the 

 F 2 matings, for the observations to be in defect in the 

 1 ' Over 30 " class and in excess in the ' ' Zero ' ' class. The 

 explanation of this is undoubtedly, as has been pointed 

 out in the detailed paper, to be found in disturbing 

 physiological factors. The high producing hen, some- 

 what like the race horse, is a rather finely strung, delicate 

 mechanism, which can be easily upset, and prevented 

 from giving full normal expression to its inherited 

 capacity in respect to fecundity. 



The writer has no desire to generalize more widely 

 from the facts set forth in this paper than the actual 

 material experimentally studied warrants. It must be 

 recognized as possible, if not indeed probable, that other 



14 With exception of one set of matings discussed in full in the complete 



