Physiology of Regeneration 621 
shows a considerable reduction, the decrease being on the average 
almost two segments. The percentage of new segments is onl 
30, and as compared with that of the control (40.7) shows that 
under the action of the chloretone there were formed 10 new 
segments less to every 100 old segments than under normal 
conditions. 
The experiment repeated in 1908 yielded practically the same 
result, as will be seen from the Table XIII. 
TABLE XIII 
Chloretone 
August 24 to September 4 (1908) 
CHLORETONE CHLORETONE 
| | 
CONTROL | 
| 0.001 per cent | ©.005 per cent 
Number of segments 
Old Regenerated * Old | Regenerated Old Regenerated 
14 4 | 18 | 2 18 2 
16 4 | 19 2 20 2 
13 4 | 20 | 2 14 S 
19 4 19 | 2 18 3 
16 5 19 | 2 19 3 
19 5 eee, 3 21 3 
15 6 17 3 17 | 4 
19 6 20 4 22 4 
21 r 
Av. 16.4 4.8 | 19 zi 18.6 3-0 
The number of regenerated segments in the control varies 
from 4 to 6, while in a 0.001 per cent solution of chloretone it 
varies fyom 2 to 5, and from 2 to 4 in a 0.005 per cent solution. 
In order to verify the results obtained from the experiments 
recorded in Table XIII and also to meet the possible criticism 
that the increase or decrease in the rate of regeneration might 
not have been caused by the substances in the solutions employed 
but have been purely accidental, the worms of all the previous 
experiments were left to continue their regeneration for a few 
