WHIGHTS OF UNDERFED YOUNG ALBINO RATS Bot 
siderably lower than in the corresponding controls. At 291 days 
of age there is an apparent decrease in the weight of the liver from 
4.19 grams to 2.56 grams, a loss of about 39 per cent (uncor- 
rected for slight difference in body weight). 
In general therefore the data indicate that in young rats under- 
fed for various periods, the liver shows a marked growth tend- 
ency in the very young rats, while in the very long fasting experi- 
ments there is usually a marked decrease in the weight of the 
liver. 
Jackson (15 b) likewise found that in young rats (three weeks 
old or more) held at maintenance the liver increases slightly 
(about 10 per cent) in weight during the shorter fasting periods; 
but in experiments extending over longer periods there is a 
decided decrease in the liver weight. 
During inanition in adult rats, the liver loses in weight rela- 
tively more than the whole body, and to a greater extent in acute 
than in chronic inanition (Jackson ’15 a). 
SPLEEN 
From table 2 it is very evident that in my young controls 
weighing approximately 10, 13 and 15 grams, the weight of the 
spleen greatly exceeds the Wistar norm for the spleen in rats of 
corresponding body-length. This is especially true for the young- 
est group. However, my average weight for the spleen (0.051 g.) 
at one week agrees more nearly with Jackson’s (’13) normal spleen 
weight (0.0425 g.) at the same age. It has been noted by Jack- 
son (13) that the weight of the spleen derived from Hatai’s 
formula is in general somewhat too low, probably because Hatai 
(without apparent justification) excluded all ‘enlarged’ spleens 
from his data. 
The weight of the spleen (table 2) at three weeks of age is con- 
siderably lower in my test rats than in the controls. In this group 
there has been an apparent decrease from 0.051 to 0.026 gram, 
a loss of about 49 per cent (uncorrected for slight difference in 
body weight). 
In the rats underfed from birth for longer periods (up to six 
