Physiology of Regeneration 629 
way, thus showing how very differently each worm reacts to 
the same medium; but in the 0.001 per cent solution not a single 
worm escaped the deleterious action of the poisons. 
In Table XXII are given the data of an experiment which will 
serve as the control for this series. 
TABLE XXII 
Control 
(For Experiments Recorded in Tables XXIII-XXV1I) 
August 31 to September 14 (1907) 
NUMBER OF SEGMENTS 
Old | Regenerated Old | Regenerated 
14 | 3 16 6 
16 3 16 | 6 
14 | 4 18 | 6 
17 | 4 18 6 
18 | 4 15 il 
16 5 17 7 
16 5 17 7 
18 5 SSS 
16 5 Average 
2 5 16.3 5.3 
17 5 
15 6 
16 6 
Ratio of new to old segment, 32.2 p.c. 
The average number of segments here is 5.3 (from 3 to 7), and 
the index of regeneration, 1. e., the ratio of the number of new 
segments to that of the old ones, is 32.2 per cent. 
Experiments with Strychnine Sulphate 
Two solutions of strychnine sulphate (1 : 1,000,000 and I : 10,- 
000,000) were employed, since the 1 : 100,000 solution was so 
highly toxic to the worms. ‘The effects upon the rate of regen- 
eration produced by both of these solutions are quite similar, 
as will be noticed from Tables XXIII and XXIV. 
