686 THE AMERICAN NATURALIST [Vol. L 



TABLE VI 



p'.O 0>9 " 0.'00216 



The table shows plainly that the daily increased re- 

 quirement from 2 to 3 years should be 0.0074 instead of 

 0.00438, or 1.7 times as much. From 3 to 4 years should 

 be 0.00696 instead of 0.00438, or 1£ times as much. From 

 4 to 5, 0.0029 instead of 0.00438, of nearly h and from 5 to 

 6 years, 0.00216 instead of no increase. 



Population No. 2 



The second population tabulated is that which began 

 with Aaggie Grace No. 2618, H.H.B., as the primary an- 

 cestress, and consists of only 456 animals. Correlation 

 tables 7 and 8 are omitted, but 9 and 10 are given, and 

 show all the data necessary for comparison with the 

 previous population. Of course, it must be borne in mind 

 that the comparison can not be too exacting, for this pop- 

 ulation is altogether too few in numbers to secure smooth 

 results especially when comparing classes. In fact, the 

 class means and deviations, Table IX, included only the 

 classes up to 9 years because of the low frequencies after 

 that age. If Tables III and IV are compared with 9 and 

 10, a remarkable agreement is noticed throughout, es- 

 pecially in the essential points which have been discussed. 



The correlation table for age to per cent, of fat is not 

 shown, but the coefficients of this table may be seen in 

 Table X. The correlation coefficient is so small that it 

 may seem negligible, but Table V shows that even with a 

 low correlation, important points might be brought out if 

 the data are sufficient. 



No endeavor will be made in this paper to enlarge on 

 the exact mathematical application of these data. This 



