TABLE XI. 
(Combined results of Tables IX and X.) 
Rats from mothers on Diet 13 and 13M. 
No. ; Age in weeks Total 
of Diet MiK4 5 6 7 8 9 10 1 12 84 Remarks 
rats Average weight in grams wks. 
10 94 0 38 42 41 38 34 27 see (1) below 
12 98 25 46 52 53 50 44 33 see (2) below 
10 97 5 41 48 50 48 40 35 see (3) below 
10 996 10 43 54 62 63 55 50 see (4) below 
110 95)=— 15 44 61 75 83 81 78 79 81 see (5) below 
11 99 20 43 58 75 85 91 96 98 97 97 54 K.at 12 wks. 
11 100 25 45 59 81 96 113 129 141 145 151 106 “ “12 “ 
11 101 30 46 62 88 108 129 147 161 172179 133 “ “12 “ 
K. = killed. D. = died. 
(1) 27 gms.—average weight at death. 
66 days=average age at death. 
(2) 33 gms.=average weight at death. 
68 days=average age at death. 
(3) 8 rats D. in 69, 68, 63, 53, 75, 73, 69, 67 days. 
2 rats K. at 12 weeks. 
(4) 6 rats D. at 65, 61, 75, 82, 72, 72: days. 
4 rats K. at 12 weeks. 
(5) 3 rats D. at 74, 74, 77 days. 
8 rats K. at 12 weeks. 
The greatest difference in rate of growth for a difference 
of 5 per cent. in the amount of milk contained in the diet, is 
found between 20 and 25 per cent. Obviously then the ration 
containing 25 per cent. of skimmed milk powder is the proper 
one to use in a study of the change in the water soluble B 
content of skimmed milk powder upon heating. 
A study of Tables 1X and X further shows a decided dif- 
ference between the animals from the two sources. Rats from 
mothers on Diet 13M grew faster and maintained a higher 
average weight than the animals from mothers on Diet 13 
alone. The young rats from Diet 13M are evidently more 
vigorous and therefore make better growth. The data shows 
that it is essential either to use rats coming from mothers on 
the same diet or to take the same number of rats from each 
diet in making up matched lots of rats for comparison. 
A typical experiment will suffice to show the variation 
among the individual animals on the same diet. The average 
17 
