PARTS OF BRAIN IN NORMAL AND UNDERFED RATS 527 
Of the various parts of the brain, the weights of the cerebellum, 
olfactory bulbs, cerebrum, and brain stem exceed those for the 
control rats of corresponding weight in the order mentioned, 
the greatest change occurring in the individuals kept at birth 
weight for various periods. In this group of individuals the 
different parts of the brain in the order above listed show an 
increase of 272, 240, 131, and 72 per cent, respectively. 
In the persistent growth of the brain in the young rats stunted 
by underfeeding, the various parts of the brain in general preserve 
approximately the same relative weight as in normal individuals 
of the same brain weight. The olfactory bulbs apparently 
form an exception to this rule, as they become abnormally large 
in the younger group of stunted rats. This apparent hypertrophy 
may be due, however, to experimental error. 
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