EFFECTS OF INBREEDING AND CROSSBREEDING. 



Table 15. — The percentage born alive. Control stock by years, 1911 to 1920. 

 [The average in each size of litter and the index, as in Table 7.] 



35 



Year. 



Size of litter. 



In- 

 dex. 



Year. 



Size of litter. 



In- 



1 



2 



3 



4 



5 



6 



1 



2 



3 



4 



5 



6 



dex. 



19}1.. 

 1912.. 

 1913.. 

 1914.. 

 1915.. 



100.0 

 81.8 

 87.5 

 82.3 

 73.7 



87.5 

 90.3 

 87.8 

 86.3 

 87.1 



81.3 

 92.4 

 92.9 

 93.3 

 92.5 



87.5 

 96.9 

 86.8 

 86.9 

 92.8 



86.7 

 91.4 

 88.9 

 85.6 

 84.6 



91.7 

 77.8 

 63.3 

 81.2 

 50.0 



86.3 

 91.6 

 89.6 

 88.8 

 89.1 



1916.. 

 1917.. 

 1918.. 

 1919.. 

 1920. . 



90.0 

 72.7 

 85.7 

 90.9 

 78.3 



92.0 

 91.2 

 87.5 

 92.7 

 88.6 



88.5 

 84.2 

 79.8 

 87.7 

 84.7 



73.8 

 84.4 

 79.4 

 87.5 

 81.6 



80.0 

 90.0 

 40.0 

 83.6 

 85.4 



16.7 



'83.' 3" 

 70.8 



86.8 

 85.2 

 82.6 

 89.5 

 84.6 



Table 16. — The percentage raised to 33 days of the young born alive. Control stock by 



years, 1911 to 1920. 



[The average in each size of litter and the index, as in Table 7.] 



Year. 



Size of litter. 



In- 

 dex. 



Year. 



Size of litter. 



In- 



1 



2 



3 



4 



5 



6 



1 



2 



3 



4 



5 



6 



dex. 



1911.. 



1912.. 

 1913.. 

 1914.. 

 1915.. 



66.7 



88.9 

 85.7 

 85.7 

 64.3 



91.4 

 92.8 

 81.5 

 94.3 



87.0 



92.0 

 89.7 

 85.3 

 90.9 

 89.2 



75.0 

 83.9 

 57.6 



84.2 

 88.7 



87.2 

 100.0 

 75.0 

 93.5 

 78.2 



72.7 



82.2 

 68.4 

 79.5 

 66.7 



85.9 



89.4 

 78.7 

 90.0 

 86.0 



1916.. 

 1917.. 

 1918.. 

 1919.. 

 1920.. 



83.3 



87.5 

 87.5 

 70.0 

 88.9 



86.4 

 86.0 

 84.3 

 88.2 

 93.5 



82.4 

 78.5 

 84.5 

 86.8 

 91.3 



77.4 

 75.3 

 85.2 

 83.9 

 80.2 



42.9 

 77.8 



"82.'6" 

 66.0 



100.0 



"45.'6" 

 52.9 



82.7 

 81.0 

 84.9 

 85.0 

 89.5 



Table 17. — The percentage raised to 33 days of all young born. Control stock by years, 



1911 to 1920. 



[The average in each size of litter and the index, as in Table 7.] 



Year. 



Size of litter. 



In- 

 dex. 



Year. 



Size of litter. 



In- 



1 



2 



3 



4 



5 



6 



1 



2 



3 



4 



5 



6 



dex. 



1911.. 

 1912.. 

 1913.. 

 1914.. 

 1915. . 



66.7 

 72.7 

 75.0 

 70.6 

 47.4 



80.0 



83.9 

 71.6 

 81.4 



75.8 



74.8 

 82.9 

 79.3 

 84.8 

 82.5 



65.6 



81.2 

 50.0 

 73.2 

 82.2 



75.6 

 91.4 

 66.7 

 80.0 

 66.2 



66.7 

 63.9 

 43.3 

 64.6 

 33.3 



73.7 

 81.9 

 70.5 

 79.9 

 76.6 



1916.. 



1917.. 

 i 1918.. 

 ; 1919.. 



1920.. 



75.0 



63.6 

 75.0 

 63.6 



79.5 



78.4 

 73.7 

 81.7 

 82.9 



72.9 

 66.1 

 67.4 

 76.1 

 77.3 



57.1 

 63.5 

 67.6 

 73.4 

 65.4 



34.3 

 70.0 

 0.0 

 69.1 

 56.4 



16.7 



"37.'5" 

 37.5 



71.8 

 69.0 

 70.1 

 76.0 

 75.8 



Table 18. — The average birth weight in grams. Control stock by years, 1911 to 1920. 

 [The average in each size of litter and the index, as in Table 7.] 





Size of litter. 







Size of litter. 





Year. 





In- 

 dex. 



Year. 





In- 



























dex. 





1 



2 



3 



4 



5 



6 







1 



2 



3 



4 







6 





1911.. 



92.8 



89.8 



77.1 



64.8 



64.3 



57.8 



80.0 



1916. . 



89.2 



85.0 



70.1 



56.8 



48.6 



50.3 



73.8 



1912.. 



115.4 



94.8 



85.9 



72.9 



67.0 



60.0 



88.9 



1917.. 



99.5 



83.4 



69.5 



57.8 



62.5 





74.3 



1913.. 



110.2 



90.6 



81.1 



70.2 



60.5 



53.5 



84.7 



1918.. 



109.5 



85.6 



68.2 



65.8 



48.3 



47.8 



77.1 



1914. . 



105.1 



101.1 



83.6 



73 6 



69.3 



58.9 



89.0 



1919.. 



105.4 



95.3 



80.5 



69.5 



62.2 



58.7 



85.2 



1915.. 



98.2 



94.2 



83.4 



68.7 



61.3 



47.0 



85.2 



1920.. 



118.0 



90.4 



80.8 



69.2 



59.2 



45.8 



85.1 



