Amount of Tail Regenerated to Removed 1n Tadpoles 437 
Experiment 8. Temperature, 82° F. No Food Given 
This experiment was made with twenty tadpoles, average body 
length 45 mm. One-half of these, Series EE, was injured by the 
removal of an average amount of 5.1 mm. of tail; the other half, 
Series FF, 10.2 mm. ‘The object of this experiment was to obtain 
additional data concerning the relation of the amount regenerated 
during the first few days after the infliction of the injury, to the 
amount removed. ‘These tadpoles (see Fig. 3, and Table 18) 
also ceased regenerating before the entire amount removed had 
been restored. Series EE ceased to regenerate after having 
regenerated 2.3 mm., 47 per cent of the amount removed, on 
the ninth day. Series FF regenerated until the nineteenth day, 
when its average amount was 4.4 mm., 44 per cent of the 
amount removed. ‘This experiment lasted twenty-two days. 
Experiment 9. Temperature 70° F. Food, Raw Beef and 
Spirogyra 
Two series, Series GG and HH, of twenty tadpoles each, body 
length 37 to 42 mm. constituted this experiment. Its object was to 
ascertain the constancy of the regenerated part after regeneration 
ceased. From Series GG 5 mm. of tail were removed; from Series 
HH, 10 mm. Both series were kept on top of a table in a room 
whose average temperature was about 70° F., for forty-two days. 
Series GG ceased regenerating on the eleventh day with 40 per 
cent of the part removed, restored. Series HH did not regener- 
ate after the nineteenth day, its final per cent regenerated being 39. 
These per cents remained the same until the experiment was 
discontinued. 
Experiment 10. Temperature,74°F. No Food Given 
The eggs, from which the animals used in this experiment 
hatched, were brought into the laboratory on April 10, 1908. ‘The 
tadpoles hatched out six days later. When they were a week old, 
thirty-two, of an average body length of 12.2 mm., were chosen. 
Four series were used, a control of uninjured tadpoles and three 
