WEIGHTS OF UNDERFED YOUNG ALBINO RATS Syl 
The weight of the trunk (table 1) is also variable, but in the 
majority of cases averages slightly lower in my test rats than in 
the controls. The differences, however, are small, and there- 
fore, as in the case of the lower extremities, are of questionable 
significance. 
On the whole, therefore, the data indicate that the weights of 
the extremities are practically normal in the test rats as compared 
with the younger controls of corresponding weight. The slight 
increase in the head, especially in the older groups, is apparently 
compensated for in most cases by a corresponding decrease in 
the weight of the trunk. Considerable allowance should be made, 
however, for experimental error and normal variability. 
Jackson (15 b) in somewhat similar experiments noted no 
distinct change in the body proportions. There was, however, 
an apparent slight increase in the head, counterbalanced by a 
corresponding decrease in the trunk and extremities. During 
inanition in adult rats, apparently both the head and the extremi- 
ties increase in relative weight, whereas the trunk decreases (Jack- 
son 715 a). 
INTEGUMENT 
In my young test rats underfed from birth to six and ten weeks 
of age, the weight of the integument (table 1) is considerably 
lower than in the controls. At 10 weeks of age the average de- 
crease from 3.9 to 2.0 grams amounts to a loss of about 48 per cent. 
Jackson (’15 b) likewise observed that the integument suffers 
a considerable loss in weight in young rats held at maintenance 
for various periods. For my test rats underfed from birth to 
three weeks, however, the relative weight of the integument 
averages 21.13 per cent of the body weight, as compared with 
21.05 per cent for the younger controls of corresponding body 
weight. Thus it is evident that in rats underfed from birth to 
three weeks there is practically no change in the weight of 
the integument, which is in niarked contrast to the loss suffered 
in the test rats fasting for longer periods. The greater severity 
of the longer fasts as compared with the shorter period may 2c- 
count in part for the differences observed. This may be due to a 
