GROWTH OF A TRANSPLANTABLE TUMOR IN MICE ad 
TABLE 2 
COMMON BACK-CROSS 
WEEKS 
+ - % + - - % + 
eee 4. LAA 75 391 16.1 54 145 ial 
Se Lae ae. 60 371 13.9 41 154 21.0 
21) a Oe 48 398 10.7 24 169 12.4 
Sad nad cil. 31 364 7.8 26 165 13.6 
Gi tee ah ieai 19 338 5.3 25 166 13.1 
233 1862 11.12+0.46] 170 799 | 17.54+0.83 
Difference 6.42+0.95 
On4exX PE: 
TABLE 4 
~ COMMON BACK-CROSS 
AGE 
- - % + ~ - % + 
DAE A RI 4m 60 438 12.0 30 120 20.0 
BRON awe 51 340 13.0 24 150 13.8 
MOI sect 41 356 10.3 25 219 10.3 
DIG 52 425 10.9 19 25 43.1 
1 ete 29 303 8.7 72 285 20.2 
233 1862 170 799 
TABLE 5 
COMMON BACE-CROSS 
AGE SE 
= % + + - % + 
PEON wet ee ee 133 908 | 12.87+0.6 69 432 | 13.77=1.05 
BPO el PR. 100 954 | 9.49406] 101 367 | 21,581.28 
Diff.-3=38 +0.85 
about 4 X the P.E. 
Diff. 7.81+1.65 
4.6 X P.E. 
In the back-cross (B.C.) series, a very interesting distinction is 
found. The lower age group shows a percentage of 13.77 41.05, 
being thus not significantly different from the lower age group 
ef the (N) series. The upper age group, however, is very dif- 
