WEIGHTS OF UNDERFED YOUNG ALBINO RATS 327 
VISCERA 
The weight of the visceral group as a whole (table 1), including 
the abdominal and thoracic viscera, brain, spinal cord and eye- 
balls, in the rats underfed from birth to three, six and ten weeks 
of age, average constantly higher than in the corresponding 
controls. The increase in absolute weight amounts to approxi- 
mately 28, 29 and 38 per cent in the test rats at three, six and ten 
weeks respectively. In the rats underfed from 21 to 412 days 
of age the increase is less marked, while in the test rats weighing 
75 grams at 291 days there is an apparent decrease in the weight 
of the visceral group from 13.68 to 11.19 grams, a loss amounting 
to approximately 19 per cent. 
From the foregoing, it is evident that in rats underfed from 
birth to three, six and ten weeks of age, there is a distinct increase 
in the weight of the visceral group. In the older test animals 
the changes are less marked, in some instances actually showing 
a considerable loss in weight. My data, however, indicate an 
increasing tendency to loss of weight in the visceral group in 
prolonged retardation of body growth, although the individual 
viscera differ in this respect, as will appear later. 
Jatkson (15 b) likewise found the visceral group to show a 
distinct increase in weight in rats kept at maintenance from three 
to six, eight and ten weeks of age, but found no essential change 
in the [ater periods. According to Jackson (’15 a) the visceral 
group undergoes little change in relative weight in adult rats 
during acute and chronic inanition. 
‘REMAINDER’ 
The weight of the ‘remainder’ (table 1), which includes some 
small unweighed organs, fat, and body-fluids, was obtained by 
deducting the weight of the integument, skeleton, musculature 
and viscera from the net body weight. The intestinal contents 
are therefore not included. 
In the rats underfed from birth to three weeks of age the ‘re- 
mainder’ has apparently suffered an average decrease from 1.843 
to 1.092 grams or a loss of approximately 40 per cent, which 
