236 NAOKI SUGITA 
the starvation. Thus in those severely underfed the difference is 
higher than in those less severely underfed. 
4. The shape of the cerebrum in the underfed is slightly elon- 
gated as compared with that of the standard with the same brain 
weight and approximates that for the same age. As the result of 
underfeeding, the growth of the central nuclei seems to be more 
arrested in width than in length and the changes in the growth 
in the cortex in thickness matter little for the shape of the 
cerebrum. 
5. The thickness of the cortex is on the average 10 per cent 
greater in the underfed in the localities I, II, VI, and VII than 
in the standards for the same brain weight. By averaging accord- 
ing to the entire section, the average thickness in the sagittal 
section of the underfed exceeds that of the standard by 5.3 per 
cent and in the frontal section by 8.7 per cent. The general 
average thickness of the cortex in the underfed is consequently 
greater by about 7 per cent than the standard for the brain of the 
same weight. The localities which normally show the higher 
rate of increase in thickness during the postnatal growth are 
those which are notably greater in the cortical thickness in the 
underfed brains. 
6. The relative volume of the cerebral cortex, computed by the 
- formula L.F x W.D x T, is generally smaller in the underfed 
than in the standard for the same age. In the underfed brains 
weighing up to 1.0 gram (that is, under sixteen days of age), it is 
on the average less by 16 per cent or more, while in the underfed 
brains weighing more than 1.0 gram it is 6 per cent greater than 
the standard. So it may be said that, in rats underfed severely, 
the cortical volume is considerably retarded in growth in early 
period of development, but this is somewhat compensated or 
overcompensated later when the brains attain the weight of more 
than 1.0 gram or in age of more than sixteen days. 
7. The cell density in the cerebral cortex, represented by the 
sum of the number of pyramids in the lamina pyramidalis and 
the number of nerve cells in the lamina ganglionaris in two unit 
volumes of 0.001 mm.’, is considerably higher in the underfed 
than in the standard rat for the same age. The excess in cell 
