EXPERIMENTS ON THE FORE LIMB OF AMBLYSTOMA 423 
TABLE 1 
Showing results of extirpation of circular areas of body wall of given diameter; 
wound not covered 
WOUND NOT CLEANED WOUND CLEANED 
5 d i) db, | & o 2 2 
DIAMETER OF 8g ae, xe} ae) 8 28 ss 3 
EXTIRPATED AREA oa or: By Total gz 2 Z g og Total | E 
gs a} oo ro) he 
s*|3"|4 es" |8"| 4 ce 
Not recorded...| 11| 10] 4 | 25 (21) | 52.4, 0 | te 9) 
3 somites...... 19 1 A242 20) e iO 5n Ol Sa eee 9 134 (25)| 52.0 
31 somites..... 1 O10 pee (L) 1 0 Ones a) 
33 somites..... 111 23) 81 |215 (184).| 82-8)— 3) 1S Me is2 (21) 14.3 
4 somites...... 14 DF ame Sha (LG) alee leenee OF eels) Sad) 
42 somites..... 2 0; 0 Din (2) 
hotaleeeaae 158 | 36 | 91 |285 (194) | 81.4; 19] 33) 384 |86 (52)] 36.5 
*Tn calculating the percentages the number surviving and not the whole 
numbers of operations has been used. Percentages are given only in those 
classes where the number of cases is sufficiently large to be of significance. 
The standard wound, which was made in the largest number 
of cases, was 34 somites in diameter, including the area ventral 
to the third, fourth, fifth, and half of the sixth myotomes. The 
wounds of four segments in diameter took in usually the region 
extending from the third to the sixth somites, inclusive, though 
in one case the place of the wound was shifted one segment, 
and in ten other cases a half segment toward the head, thus 
including in the latter that portion of the body wall between 
the posterior half of the second somite and the anterior half 
of the sixth inclusive. 
As shown in table 1, the result of the experiment depends in 
a certain measure both upon the size of the extirpated area and 
the completeness of the removal of tissue. Taking all of the 
experiments without reference to size, 81.4 per cent of the cases 
with ordinary wound regenerated limbs while only 36.5 with 
cleaned wounds did so. In both sets of experiments, increase in 
the size of the wound over three somites considerably reduces the 
proportion of regenerated limbs. High mortality of the large 
clean-wound class has considerably diminished the number of 
