GROWTH OF THE CEREBRAL CORTEX 191 
TABLE 4 
Show ng for each litter group in this study the average age, duration of isolation 
denoted by the percentage of the life span, observed body weight, compared with the 
standard body weight for the same age, and observed rain weight, compared with 
the standard values for the same age and the observed body weight, respectively. 
Standard values were all calculated by the use of the formulas given in ‘The Rat’ 
(Donaldson, '15). Within each litter the starved animals were divided nto two 
groups, T I having brains weighing less than 1.0 gram and T. II having brains 
_ weighing more than 1.0 gram. The contro! animals were also grouped in the same 
way into two groups, C. I and C. II. Averages were taken within each group. 
In lines designated ‘percentage difference’ (abbreviated ‘per. diff.’), the devia- 
tions of the observed measuremonts from the standard values were given in per- 
centage, the respective standard values being taken as standards of comparison. 
At the foot of the table, the average as to the test and control groups are given and 
the percentage differences from the standards are also ca'culated 
Za 
0% | BODY WEIGHT BRAIN WEIGHT 
Fales| 
ape 
Mas Stand 
1) otanda- 
: TEST AVER-| Po» 
Rise tetas ani cON- SEX AGE A a Stand- Stand- eee 
TROL AGE Bo = Ob- _|ardac-| Ob- | ard ac- ees a 
: = | served jcording | served |cording eeeced 
Bo & o ee |t 
Bias to age to age body 
a weight 
days |per cent| grams | grams | grams | grams | grams 
Series I 
IN Oils at mares fl 7 — 32 7.2 | .9.7 | 0.584) 0.644) 0.441 
h 405 BG) bar 15 44 13.9 | 16.5 | 1.024) 1.048] 0.952 
(per. diff.) (—19) (— 5)} (+15) 
b, e, g Cra 3m 8 11.7 | 10.9 | 0.740) 0.750) 0.790 
1 Cra iat 17 SOM Se W278i Ogg sO 
(per. diff.) (+44) (+ 9)|(— 4) 
Series I 
1B) Be Gs al 3am 1h) 9 30 7.3 | 11.4 | 0.644) 0.775] 0.468 
i ABs JUG) al seey |) Ae) 44 ee Siar Wl O52 SOL Gor 
(per. diff.) . (—34) (—11)| (+24) 
b, d Cask Dist 6 Woh 8.6 | 0.543] 0.559) 0.437 
g, h, j Comet iris 20.5 | 18.7 | 1.144] 1.118] 1.148 
(per. diff.) Gr) Gy DiGCe G6) 
Serves I t 
Cxaerrd As MANA som, a ail) 2X0) 44 15.1 | 20.4 | 1.105) 1.146) 0.946 
(per. diff.) (— 26) (— 4)}(+17) 
b,e CLIO Bi 22— PHL AD || FF | UpsxO| WU 2HGa)) LEY 
(per. diff.) (+22) (+12))'+ 6) 
