JENKINS AND CarRLson, Nervous Impulse in Worms. 269 
ments. In attempting to make the nerve-cord-muscle prepara- 
tion the musculature is thrown into strong and prolonged con- 
traction. That of the circular musculature was the most marked 
especially at the points where the worm was fastened to the 
floor of the apparatus. This contraction of the circular muscu- 
lature was so vigorous as to prevent the longitudinal muscula- 
ture from shortening the body and thus acting on the lever. A 
—_—________ NWN 
LLLLIILISIGLIPIMISPISIIISSID IIS SDI IIIS SINIIISISILPIS SII 
Fig. 4. Arenicola sp. Antero-posterior. Length of nerve cord between distal 
and proximal electrodes: 10cm. Rate: 125 cm. persec. Time: 50d.v. 
per sec. 
dorsal longitudinal slit throughout the preparation did not les- 
sen the effect of the circular contraction, but put the prepara- 
tion in such a condition that the contraction of the longitudinal 
layer on stimulation of the cord bent the preparation to the in- 
ner side and in this way gave opportunity to attach the record- 
ing lever. The nerve cord is about 0.7 mm. in diameter and 
easily separated from the adjoining tissue. The interrupted 
current was used, since single induction shocks proved inefh- 
cient. 
EXPERIMENT NO. 3, Table IV, antero-posterior, temp. 14.5°C, July 9, 1902. 
Distal Proximal 
No. of records 12 7 
Mean latent time 0.20 sec. 0.12 sec. 
Standard deviation O.OL sec. 0.007 sec. 
Coefficient of variability 205 .06 
Length of cord: tocm. Rate: 126 cm. per sec. 
