GROWTH OF THE CEREBRAL CORTEX 225 
TABLE 16—Contin wed 
AFTER EXTRACTON 
IN 80 PER CENT AND 
90 PER CENT Standard DInT RS 
SERIES, LITTER AND TEST ASV. ETRIAG TD) |e ALCOHOU ay ENCE 
GROUP CONTROL AGE | eee a ; ofthe. FROM THE 
| Final lt} ete? Je, same age SEAS UENO 
Deane jue initial 
weight brain 
| oo weight 
days grams grams per cent per cent per cent 
Series III 
G a-g aS: 11+ 0.844 0.641 76.0 UOae, aioe 
h-j AUS JU 22— . 1.154 0.833 72.2 (2 1.0 
Average | Tl i+ | 0.753 | O.571| 76.0 | 74.2 | +1.8 
(Ser. I-III) f T. IT | 20+ ft OAS]. OLS814) |) "45298 |) S708 +2.0 
Average Cr 8— 0.700 | 0.529 | 75.8 75.3 +0.5 
(Ser. I) Cyr 18+ 1.195 0.862 (253 72.1 +0.2 
continuously with the mothers (Series IJ and III, chapter 2 and 
table 2), the loss in the brain weight is relatively less, in some 
individual cases nothing, while the body weight suffers much 
more, compared with the acutely underfed groups (Series I). 
The observed body weight and the brain weight of each indi- 
vidual in this study are plotted separately for each litter in chart 
2, A to H, according to the advancing age. Comparing the set 
of graphs both for the body weight and the brain weight within 
every litter, it is clearly seen at a glance that the courses of the 
graphs are similar, so that one, which advanced in age but has a 
smaller body weight, has also a relatively smaller brain weight, 
and vice versa. From this it is concluded that, though the 
brain, with a strong impulse to grow, regularly increases in weight 
with age and is only slightly affected by outside influence, yet 
it is controlled somewhat by the growth in the entire body. 
Thus, within certain limits, the brain weight may be said to be a 
function of the body weight: a rat reduced in body weight by 
starvation has a brain also reduced in weight and, on the other 
hand, a rat excessive in body weight for its age, through overfeed- 
ing, has an excess of brain weight for its age, as seen in the control 
groups shown in table 4. In the interrupted starvation tests 
(Series I), an average reduction of 29 per cent in the body weight 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 29. NO. 3 
