FERTILITY AND HATCHING OF EGGS. 



141 



At the outstart it will be well to examine correlation tables 

 such as have been described correlating mother and daughter 

 with respect to fertility and to hatching (|uality of eggs. Such 

 tables are given as Tables XX and XXI. 



The constants calculated from these tables are given in 

 Table XXII. 



TABEE XXIT. 



Constants Calculated from Tables XX and XXI. 



Constant. 



Fertility, 

 table XX. 



Hatching quilitv, 

 table XXI. 





13.88±1.49 

 20.61±1.0.5 



148.47±17.66 

 1.3.65±1..3S 

 19.10±0.98 



139.96±15.87 

 —0.035 ±0.072 



52 96 ±1 23 



standard deviation 



17.00±0.87 

 32 00 il 80 





47 67 ±1 80 





24.92±1 27 





52 27 ±3 32 



Coefficient of correlation 



0.031±0.072 



From this table we note the following points : 



1. The figures apparently do not indicate that there is any 

 correlation between mother and daughter with regard to either 

 of the characters considered. Neither coefficient of correlation 

 sensibly dififers from zero. 



2. The mothers, though a selected class are not less variable 

 than the daughters so far as per cent, of infertility of eggs is 

 concerned. They are much less variable than the daughters in 

 per cent, of fertile eggs hatched. In selecting i)ullets for breed- 

 ing in 1909 (i. e., "daughters" of the present discussion) partic- 

 ular attention was paid to the breeding records of their mothers 

 as regards per cent, of fertile eggs hatched. This means that the 

 mothers which are in the correlation tables XX and XXI are 

 a selected grou]), whereas the daughters in these tables are not 

 selected at all, with reference to their own fertility and hatching 

 records. While some attention was paid to fertility of eggs 

 in this selection of breeding stock, the selection was not so close 

 as in regard to ])cr cent, of fertile eggs hatched. 



3. There is a much more marked diminution of the daugh- 

 ters' mean below the mothers' mean in the case of hatching 



