OLFACTORY BULBS OF THE ALBINO RAT 209 
underfeeding, following the first month under normal con- 
ditions, left the rats but slightly longer (4 to 10 mm.) than the 
initial controls measured at thirty days. The average increase 
in weight was in about the same proportion. Compare tables 
2 to 8, for body weight and body length. 
All the rats showed extreme emaciation but this condition was 
largely masked by the condition of the coats. The hair re- 
mained short and soft, with a fluffiness which gave even to mature 
rats the appearance of plump young animals. Such emaciation 
was, of course, accompanied by great muscular weakness. 
Rats kept for long periods on the defective diet became unable 
to remove corn from the cobs. They walked with a tottering 
gait and moved about but little. 
The cyanosed condition of these animals was clearly indicated 
by the blue color of all exposed parts of the body—nose, ears, 
feet and tail. In protracted cases of underfeeding, a chronic 
palpitation of the heart developed which increased in violence 
as time went on. As a result of this, the whole body shook 
constantly. : 
All animals kept on corn up to maturity failed to breed or to 
show any sexual instinct whatever. 
Effect on brain and olfactory bulbs (compare tables 1 to 8). 
In Series A, both A; and A, show a slight increase in brain weight 
during the period of underfeeding. Under normal conditions, 
as the rat grows, the brain becomes relatively lighter in pro- 
portion to body weight. In the underfed rats the brain forms 
practically the same proportion of the total body weight as in 
the initial control rats (agreeing with Jackson’s results (’15)), 
which of course indicates in the cases where growth has taken 
place that the brain has not been as much arrested in its develop- 
ment as has the rest of the body. 
After four to eight weeks of underfeeding, the rats of Series 
A, and A; had olfactory bulbs which, taken together, formed 
about the same proportion of the total brain weights as did the 
bulbs of the initial controls of the same series, showing that the 
relation of these parts of the brains had not been changed during 
the experiment. But normally the olfactory bulbs grow faster 
