336 CHESTER A. STEWART 
weight during the earlier periods (decrease of 15 per cent) but 
not later. It is evident from my results that the loss in the 
lung weight in very young underfed rats is considerably greater. 
During acute and chronic inanition in adult rats the lungs lose 
weight in about the same proportion as the whole body (Jackson 
Alioeet). 
LIVER 
The weight of the liver (table 2) in my young control rats is 
very much lower than the Wistar norm for rats of corresponding 
‘body length. The differences are especially marked in the con- 
trols weighing approximately 13 and 15 grams. My average 
value of 0.37 gram at one week, however, corresponds rather 
closely with the weight of 0.3431 gram obtained by Jackson (713) 
in rats of the same age and weight. Thus, as pointed out by 
Jackson, it seems that weights for the liver obtained by Hatai’s 
formula, especially for young rats, are much too high, at least for 
rats of the Missouri and Minnesota colonies. The difference 
appears too great to be attributed to normal variability or to slight 
differences in diet. However, C. Watson (’10) finds a marked 
decrease in the relative size of the liver in captured wild rats fed 
upon bread and milk diet used during captivity; and Jackson 
(13) has emphasized the marked and irregular variability found 
in the liver of the rat. 
In the rats underfed from birth to three, six and ten weeks of 
age the weight of the liver is considerably higher than in the cor- 
responding controls. The increase at three weeks averages about 
17 per cent. The difference is especially marked, however, at 
six and ten weeks, amounting to an average increase of about 83 
per cent in the former and 64 per cent in the latter (subject to | 
correction for slight differences in body weight). 
In the rats underfed for longer periods the liver is variable. At 
412 days of age the average weight of the liver (2.04 grams) in 
four test males is practically identical with that in the two con- 
trols (2.06: grams). The liver weight of the controls appears to 
be abnormally low, however. In the remaining groups of test 
rats underfed for very long periods the weight of the liver is con- 
