218 NAOKI SUGITA 
in diameters on the average of T. I and T. II groups: pyramids 
13.2 per cent and ganglion cells 8.8 per cent). In young brains 
which weigh less than 1.0 gram, the influence of the underfeeding 
is considerable, while in brains weighing more than 1.0 gram or of 
ages more than sixteen days we can not detect any large arrest 
in the size-development, especially of the ganglion cells (the sizes 
of the cell body and the nucleus of the ganglion cells in the 
T. II groups are quite equal to the corresponding sizes in C. II 
groups) (tables 12 and 13). These observations are in agreement 
with the conclusions reached by Morgulis (’11). 
13. PERCENTAGE OF WATER IN BRAIN 
As stated earlier (in chapter III), Litter H in Series II, in which 
a young primipara mother was entrused with seventeen young in 
order to produce a series of underfed young, was used partly 
for the investigation of the percentage of water in the underfed 
brain and partly for a histological study of myelination fae con- 
sidered at this time). 
In this Series II the development in brain weight is not so 
greatly arrested, as compared with the arrest in body growth, as 
in Series I. As already shown, in Litter F, which was treated in 
a similar manner, the brain weight is on the average 9 per cent 
low, but in this Litter H it has been possible to arrest the brain- 
weight growth on the average by about 12 per cent, compared 
with the standard of the same age (compare table 4). 
Table 14 gives for each individual examined in this litter the 
sex, the age, the brain weight, and percentage of water in the 
brain, each accompanied by the standard percentage of water 
contained in the brains of the same age and sex and also of the 
same weight and sex. The differences are given in special 
columns. 
By obtaining averages, it is found that the underfed brain 
contains slightly (0.48 per cent) more water, when compared 
with the normal brain of the same age and somewhat (1.4 per 
cent) less water, when compared with the normal brain of the 
same weight. This means in terms of the percentage of water, 
