434 Max Mapes Ellis 
results agree exactly with those obtained in Experiment 4. All 
of the series, except those with 20 mm. removed, ceased regener- 
ating after about 47 per centum of the amount removed had been 
regenerated. All of the tadpoles of Series Y (20 mm.) died during 
the first few days after the operation. 
TABLE 6 
AMOUNT |PERCENTUM]| DAYS OF 
| AMOUNT 
| REGENER- | REGENER- | REGENER-~ 
REMOVED 
ATED ATED ATION 
mm mm 
SenestU ki nwrerictadeles sielcist s sy igciaeentgawe Bye | ite 48 9 
Sais Si caosedop onic BE UA sem oor GOS am eredin sc 5.0 2.4 48 II 
Eres acate ee dse Riteces e.oicts ee ete ots talty Acheter 10.1 4-9 49 15 
SERIES Mcrae ens eivee eee sess sis ar a ave atenoaiow able 14.9 7.4 49 19 
Series, Vor earsitra ce esis emacs yates ots 20.1 died 
Experiment 6. Temperature, 82°F. No Food Given 
Twenty-four small tadpoles, body length 18 to 20 mm., were 
divided into two series, AA and BB. The average amount 
removed in Series AA was 2.5 mm. of tail; in Series BB, 5.2 mm. 
(See Table 14.) 
Series AA ceased to regenerate on the fifth day after the opera- 
tion, with an amount of I.4 mm., 55 per cent of the amount 
removed; Series BB continued to regenerate until the seventh day. 
Its final amount of regeneration was 2.9 mm., 52 per cent of 
the amount removed. ‘The only point of difference between these 
results and those of Experiment 2, since the amount regenerated 
was proportional to the amount removed, is the absolute per cent 
of regeneration; this is higher in the present experiment. [wo 
things probably contribute to this difference, the tadpoles are 
younger and the temperature is higher. Both of these factors 
increase the rate of regeneration. 
As originally planned, it was intended that Experiment 6 should 
supply some data concerning the surface and the volume of the 
regenerated parts, but the difficulties encountered in computing 
these values by the method chosen were so great as to render the 
