JEssai/ on the Interpretation of Milk Records. 173 



correlation of milk yield with quality, or other characteristics. 

 It should also be of value in dealing with the question of 

 heredity. 



It is not intended to discuss here the inheritance of yield, 

 but one example of the use of the R.M. may be given in this 

 connection. The following diagram shows the deviation of 

 forty-eight daughters of one bull from their mothers. 

 Daughters whose R.M. do not differ by more than three quarts 

 from that of their mother are entered on the zero line ; wider 

 divergencies are calculated in percentages and entered on the 

 right or left of the zero line according to whether daughters 

 are greater or less than their mothers. This bull from general 

 observation was thought to be a good one, but it is clear from 

 the diagram that it has tended to lower the average yield 

 capability. 



Fig. 9.— Bull No. 9. 1st Calf R.M. Deviations F,. 



50^ 40^ 30jgr 



Less than mother. 



20^ 30^ 40^ 50J 



More than mother. 



Note 2. Prof. James Wilson's figures. — In a paper on the 

 inheritance of milk jield' this writer gives a method for 

 estimating lactations totals. He says, " The calculation is to 

 multiply the average daily yield in pounds over two or three 

 weeks at the maximum by about twenty, and the result gives 



1 Proc. Royal DuMin Society, June, 1911. 



