EXPERIMENTS ON THE FORE LIMB OF AMBLYSTOMA 425 
TABLE 2a 
Showing frequency of regeneration after operations in the several stages 
WOUND NOT CLEANED WOUND CLEANED ALL EXPERIMENTS COMBINED 
STAGE ; Cases Per C: Cases Per mend Per 
cee eek cant ree ead Sea or raise Total cases oe 
erated erated | erated erated erated | erated carded era ted 
25 4 0 0 1 2 U (5) 
26 3 0 2 3 0 8 (8) 
27 8 2 80.0 3 11 21.4 4 | 28 (24)| 45.8 
28 20 0 100.0 2 11 15.4 20) || 53 (33)| 66.7 
29 65 | 12 84.4 10 25 || 28.6 41 |153 (112), 66.1 
30 26 5 83.9 5 9 SOEG 28 | 73 (45)| 68.9 
31 12 3 80.0 2 3 28 | 48 (20)| 70.0 
32 4 4 z, 0 4} 14 (10)| 60.0 
33 14 10 58.3 1 0 4 | 29 (25)| 60.0 
Miscellaneous* 4 5 0 2 (i) aly (ally) 
MO Galen esa 160 41 27 | 65 137 |430 (293) 
* Stage not recorded or else outside above limits. 
TABLE 28 
Showing frequency of regeneration after operation in the younger and older groups 
of stages, respectively 
ALL EXPERIMENTS 
D D 
WOUND NOT CLEANE WOUND CLEANED COMBINED 
erach Cases Per Cases Per Cases Per 
ses ‘ases 
eal not cent Cae) not cent ate not cent 
regen- | regen- 8 egen- | regen- en- = 
erated |. T°8° regen- | crated | T° TER? erated | T° BEN 
erated | erated erated | erated erated | erated 
or 
Stage 29 or under...| 100| 14 | 87.7| 17 fl |) AS 600) \) Ke |) as 
Over stage 29....... 56 aD, 71.8 10 12 45.5 66 34 
4.3 
6.0 
or) 
One point stands out, however, which may possibly be of sig- 
nificance, though no altogether satisfactory explanation is ap- 
parent. In the group with wounds not cleaned a higher per- 
centage of regenerating cases is found among those operated 
in the younger stages, while in the group with cleaned wounds 
the higher percentage is at the opposite end of the series. This is 
brought out more clearly when the experiments are divided 
into but two classes, comprising respectively the cases operated 
when older than the standard operating stage and those in or 
below it (Table 2b). The lower percentage of regeneration in 
