FECUNDITY AND WEIGHT AT BIRTH 



25 



give regular results, but if we take the extreme records, we find 

 that in the small litters of 6.5 the individual birth weight is 

 higher than in the large litters of 10 or more (table 5). 



The failure to get regular results is probaby due to the small 

 number of cases here used. 



TABLE 5 

 The influence of the size of the litter on the individual birth weight 



Finally, if we take the individual birth weights as the criterion 

 and compare the birth weights under 4.5 grams (for the male) 

 with the birth weights of 5 grams or more (for the male) it ap- 

 pears that the heavier birth weights are associated with the heav- 

 ier weight of the mother as we should expect from table 4. At 

 the same time it is to be noted that the age at which the heavier 

 birth weights are recorded is greater. 



TABLE 6 

 The individual birth weight in relation to body weight of mother 



These relations exhibited by table 6 and based on this small 

 number of stock Albinos agrees with those already determined 

 by King on a much larger series which combines the data here 

 used with a large series of litters from inbred Albinos. 



This agreement shows that in these respects there is no signi- 

 ficant difference between the stock Albinos and the inbred strain 



