GROWTH OF THE CEREBRAL CORTEX PPA 
is accompanied by 8 per cent reduction in the brain weight in the 
test rats, and an excess of 14 per cent in the body weight by an 
excess of 6 per cent in the brain weight in the controls. These 
relations indicate that the brain weight is affected in abnormal 
conditions of nutrition during early life so that its percentage is 
altered by about one-third the percentage of the change of the 
body weight, either plus or minus, as compared with the standard 
values. On the other hand, in chronic inanition (Series II and 
III) where the young rat is not disturbed, the brain-weight loss 
was also 8 per cent against a body weight loss of 39 per cent. 
It appears, therefore, that during the early helpless period the 
brain development is highly disturbed by the changes in the 
environmental conditions represented by removal from the nest, 
but that when the rats are not disturbed it is much less affected 
even by severe underfeeding. 
Table 17 gives for each group in this study the brain weight— 
body weight ratio, in percentage value, paired with the ratio 
obtained from the corresponding standard values for the same 
age and sex, calculated on the data given in table 4. The com- 
plete data for each individual are contained in table 17a (un- 
published) from which table 17 was condensed. In the underfed 
the above ratios are all higher than the standard, as was to be 
expected, while in the controls lower ratios are sometimes seen, 
which, in turn, means an overgrowth of the body. The average 
differences for each litter and group are given and the values are 
indicative of the severity of starvation combined with the special 
characteristics of the litter. Within each litter the range of the 
differences is narrow but the evidence for this statement is fur- 
nished by the unpublished detailed table 17 a. 
16. A DISCUSSION ON THE CHANGE IN SHAPE OF THE CEREBRUM 
In my first paper (Sugita, 717) it was stated that the Albino 
cerebrum becomes relatively longer as the age advances. During 
starvation, the rate of increase in every dimension diminishes 
considerably, but the relations between the three dimensions re- 
mains nearly unchanged, so that, as a result, the underfed brain 
is somewhat elongated in shape in comparison with the standard 
