JENKINS AND Carson, WVervous Impulse in Worms. 279 
tances were measured while the pieces were crawling in the 
aquarium and represent very nearly the length during the nat- 
ural extension of the worm. 
Single induction shocks applied to the distal point of 
stimulation produced a single prolonged contraction. After 
three or four reactions, single shocks failed at the distal 
point, then the break or make of the direct current was still 
efficient. Since the largest preparation was no more than one- 
fourth the length of the whole worm, it is impossible to say 
whether through the whole length of the cord a single induc- 
tion shock would prove efficient. 
ame en mn PGS 
Dee 
ae INN ee 
SLPLISLPPPPFSSL PS LPGPPLSP SPP SSISLS SPS SPSS IVS SLI ISI III 
Fig. 11. Nere/s virens. Antero-posterior. Length of nerve cord between dis- 
tal and proximal electrodes: 6.5 cm. Rate. 81.2 cm. persec. Time: 56 
d.v. per sec. 
Good reactions were obtained from one portion 24 hours 
after its separation from the rest of the body; in other pieces 
48 hours later only feeble responses were obtained; however 
one piece lived three weeks in the aquarium, when it was de- 
stroyed by an accident. In one piece the rate was taken in the 
antero-posterior direction, in the other postero-anterior direc- 
tion. The rates 89 and 73.4 respectively, differing as they do, 
may not be taken, in the absence of other experiments, as con- 
clusive evidence that the rates in the two directions differ. 
EXPERIMENT No. 1, Table XI, antero-posterior, July 20, 1901. 
Distal | Proximal 
_— - | = - 
No. of records 27 ES 
Mean latent time 0.183 sec. 0.096 sec. 
Standard deviation 0.016 sec. 0.007 sec. 
Coefficient of variability .08 Or 
Length of cord: 6.5 cm. (25 segments). 
Rate: 73.4 cm. per sec. 
