622 Sergius Morgulis 
weeks more. They were then all transferred to normal sea- 
water under conditions as nearly alike as possible, but I was 
unable to detect any differences in the regenerating capacity of 
~ the worms during this period of time, although chloretone, 
especially the stronger solutions, seems to leave an after effect. 
Second Series of Experiments 
These experiments were performed in order to test the effect 
of atropine and digitalin on worms in the process of regeneration. 
Stock solutions of 0.001 per cent of atropine sulphate and of 
digitalin (Merck) were prepared in sea-water, and the solutions 
used in the experiments were made by diluting these stock solu- 
tions. — 
In all the experiments to be described hereafter the regenerating 
worms were submerged in the solutions for the full period of their 
regeneration. ‘The water in the experiments and in the controls 
was frequently changed. The worms used in these experiments 
were collected on the same day and from the same locality. 
In Table XIV are summarized the data pertaining to the con- 
trol experiment. 
It will be seen from this table that the average number of regen- 
erated segments is 6.1 (4 to 8 segments), and that the ratio of 
the number of new to that of old segments is 36.3 per cent. 
Experiments with Atropine 
The atropine solutions were of two different strengths: 0.001 
and 0.0001 per cent. The effect produced by these solutions 
upon regenerating worms, so far as the rate of regeneration is 
concerned, is recorded in Tables XV and XVI. 
In Table XV the average number of regenerated segments 
(3 to 6) is 4.7, which presents a decrease as compared with the 
control. In Table XVI the number of regenerated segments 
varies from 3 to 8, with an average of 6.4, showing that the atro- 
pine in such a dilute concentration is ineffective. 
Expressing the effect of the stronger atropine solution upon the 
rate of regeneration of new segments in terms of percentages, it 
