PARTS OF BRAIN IN NORMAL AND UNDERFED RATS 525 
As is shown in table 3, in both the normal and test rats, the 
cerebellum manifests the strongest growth power, the olfactory 
bulbs, cerebrum, and brain stem following in the order mentioned. 
The perfect agreement in this respect between the control and 
test individuals can hardly be considered a mere coincidence, but 
more probably is the expression of inherent normal tendencies. 
Furthermore, it has been pointed out that with the growth of 
the brain in the stunted rats, the various portions of the brain 
undergo practically the same changes in relative size as found in 
normal animals of the same brain weight. The olfactory bulbs 
which show an overgrowth (in the younger group) apparently 
form the only notable exception to this rule. In general, there- 
fore, it appears that no:mal growth tendencies foreshadow the 
character and the amount of the changes that accompany 
growth of the brain during underfeeding. In other words, the 
growth of the brain in the stunted rats appears normal, so far as 
the changes in the size of the constituent parts is concerned. 
The tendency for the different brain subdivisions to maintain 
largely the normal proportions during starvation is in marked 
contrast to the change in the relative weights produced among 
various organs of the body as to result of underfeeding. Jack- 
son (715, p. 152) also noted that in some cases (e.g., liver, alimen- 
tary canal) there is a certain degree of parallelism between the 
normal growth tendency and the behavior of organ weight in 
young rats when the body weight is held constant. Further- 
more, the greatest number of organs showing growth during 
maintenance (constant body weight) occurs in very young rats 
during the normal period of most rapid growth (Stewart, ’18). 
The above-mentioned principle therefore applies not only to the 
brain and its various subdivisions, but also to many other organs. 
However, there are certain exceptions to this rule, as pointed out 
by Jackson. 
It is interesting to note that the marked growth of the brain 
in rats stunted by underfeeding occurs only at a period when the 
normal increase in size is still due partly to cell multiplication, 
especially in the cerebellum (Allen, 712). This is a phase of the 
inanition problem worthy of further investigation. 
