OLFACTORY 
BULBS OF 
TABLE 23 
INITIAL CONTROLS FOR TEST ANIMALS 
THE ALBINO RAT 
INITIAL CONTROLS FOR CONTROL ANIMALS. 
(DEFECTIVE FEEDING EXPERIMENT) 
Average 
Average 
Average Per cent Average Per cent 
Litters brain BlRaEry of brain Litters brain pliantory: of brain 
weight weight | weight weight weight weight 
grams grams grams grams 
DN A AC e se 1.3805 | 0.047 3.60) |L,.N; O}) 1.431 0.058 3.69 
405 Wh, We 
Test 
———............ ss 91% 89% 
Control 2 g 
TABLE 24 
INITIAL CONTROLS FOR CONTROL ANIMALS 
HSER (CONIA O} ES IAC alsin! Lengel cues, (DEFECTIVE FEEDING EXPERIMENT) 
Average ay oto Per cent Average pvereee Per cent 
Litters brain cenibe of brain | Litters brain Opelika Y! of brain 
weight weight weight weight woicht weight 
grams grams grams grams 
XGA) Vereen asa eek 1.340 0.051 Bie eb, WU 1.458 0.055 3.76 
and T 
Test 
———_............... 92 92 
Control 7 7 
But, be this as it may, we find the bulbs of these test animals 
actually 6 per cent heavier than those of the controls, the bulbs 
making 4.74 per cent of the total brain weight, while those of 
Series A controls were only 4.23 per cent of the total weight of the 
brain. 
Since we have no true control series for comparison, we can 
not, of course, draw conclusions as to the absolute gain in brain 
weight after exercise. But of the gain in olfactory bulb weight 
in exercised animals, there seems to be no doubt. 
When we turn to table 25 and note that the average percent- 
age weight for the bulbs in case of 29 normal rats (59 to 88 days 
old) is 4 per cent, while a study of table 13 shows there was no 
rat there recorded (save one sick one) in which the per cent fell 
below 4.21 per cent, while the average was 4.51 per cent, we 
must be convinced, I believe, of the reality of the effect of exercise. 
For the older rats, likewise, when we compare tables 19 and 25, 
