102 C. M. JACKSON AND C. A. STEWART 



with abnormally low body weights, causing previous depres- 

 sion of the curves. Although in five of the twenty-three test 

 rats (table 1) the maximum body weight reached or exceeded 

 slightly that of the controls of the same sex in the same litter, 

 the average for the test rats for each sex remains definitely 

 below that of the controls. 



The curves of body weight for the rats refed after under- 

 feeding from birth to six weeks of age are shown in chart 2. 

 This is a small group, the males including 1 test and 1 control 

 rat from litter St, 61, the females including 2 test and 2 control 

 rats from litters 52 and 71 (table 1). Although the normal 

 maximum body weight was not reached by either male or female 

 controls (in the former, on account of a wounded foot), they 

 remain at all times above the test rats of corresponding sex, 

 as shown by the chart and by table X- 



In chart 3 are shown the curves of body weight for the rats 

 refed after underfeeding from birth to about ten weeks (average 

 72 days) of age. They include nine litters, with 10 test males, 

 9 test females, 8 control males, and 3 control females (table 1). 

 The sudden rise in the curve for control males at 490 days is 

 not due to an actual increase in body weight, but to the sur- 

 vival of a single rat of unusually large size. Similarly in the 

 test females, the continued rise in body weight after 340 days is 

 due partly to the elimination of one rat (St. 111.8) which was 

 very low in final weight, and to the survival of an unusually 

 large test rat (St. 111.4). The final gross body weight of the 

 latter (212 grams) was 1 gram above that of the surviving con- 

 trol (St. 111.5). In no other case did the maximum body 

 weight of a test rat in this group reach that for the control of 

 the same sex in the same litter. Even in this case, the net body 

 weight (gross weight minus intestinal contents) of the test rat 

 was 191 grams, while that of the control was 198 grams. Both 

 were pregnant when killed. Except at this point, the average 

 body weights for the test animals, as shown by the chart and 

 by table 1, remain definitely below those for the controls of the 

 same sex. 



