\ 
Amount of Tail Regenerated to-‘Removed in Tadpoles 425 
sions of this table. The average body length of the animals used 
in this experiment was 40 millimeters. “The measurements were 
made on the twelfth day after the operation. 
Experiment I. T emperature, 74° F. Food, Spirogyra 
Sixty tadpoles, body length 37-42 mm., were divided into 
three series—A, B, and C,—of twenty individuals each. The 
injury given Series A was the removal of 7 mm. of tail; Series B, 
Io mm.; Series C,13 mm. ‘This experiment was maintained under 
the same conditions as the preliminary experiment just mentioned, 
which it was intended to duplicate. “[welve days after the opera- 
tion, the amounts of regeneration were measured. ‘The average 
amounts regenerated are given in Table 2. 
TABLE 2 
AMOUNT AMOUNT PER CENT 
REMOVED REGENERATED REGENERATED 
SETIGE PA era ieas arcrite wisietalcis tua) sienere c orgpauayslso/a.e e opanauete 7 2.66 38 
CGE Lost aude Rapp net deca cu DER Den eennnm sadist 10 3-68 37 
Sener Ge tactician folate ck nlsnshecone aineieceieels 13 4.81 a7 
The per cent regenerated by each series during the twelve 
days of this experiment was approximately the same, although the 
amount removed in each case was different; that is, the length of 
the regenerated part was proportional to the amount removed. 
This experiment confirms the preliminary experiment as regards 
proportional regeneration, but it is obviously incomplete, since 1 
states the relation between the amount removed and that regener- 
ated at but one time after the operation, namely the twelfth day. 
Experiment 2. Food, Spirogyra and Raw Beef 
This experiment was designed to ascertain the relation between 
the amount removed and that regenerated at some other time than 
the twelfth day after the operation. The effect of temperature 
on the amount of regeneration was also noted. 
One hundred and sixty tadpoles, body length 37 to 42 mm., were 
placed in four large glass battery jars, forty in each jar. Bese 
