PHYSIOLOGICAL ACTION OF VENOM OF BLACK SNAKE. 249 
upon motor nerve terminations. The symptoms of interference 
with the nervous system cannot be accounted for in this way. 
(i.)—Eaperiments with Frogs. 
In all these experiments the sciatic nerve on one side was 
dissected out fora length of about 1 cm. and a ligature passed 
under it and tied around the limb, but so as to exclude the nerve. 
The poison was then introduced either into the dorsal lymph sac, 
or into the peritoneal cavity, and was unable to reach the ligatured 
limb which was cut off from all circulation. As soon as all move- 
ment either voluntary or reflex had ceased, the lower half of the 
frog was cut off at the waist, the skin removed from the lower . 
half of the body and the sciatics of both sides stimulated as they 
lay beside the urostyle in the abdominal cavity. 
The capacity of the nerve to conduct impulses to the muscle, 
was ascertained by stimulating it with the induced current from 
a Du Bois Reymond’s coil, and recording the greatest distance of 
the secondary from the primary coil when a contraction of the 
gastrocnemius was caused by breaking the primary circuit. This — 
circuit contained one Daniel cell, and a moderately constant 
rapidity in opening the circuit was obtained by allowing a rotating 
cylinder to make and break a metallic contact. The cylinder was 
kept rotating at a uniform speed, and made and broke circuit with 
each revolution, The secondary circuit was short circuited by a 
Du Bois Reymond key. This was opened, when it was wished to 
stimulate the nerve, during one revolution of the cylinder, and 
then closed again. As only the minimal stimuli requisite to pro- 
duce * contraction were employed, the closing of the primary 
circuit just previous to its opening, failed to cause any contraction 
of the muscle. 
Experiment I.—Large male frog, weight 21 grammes ; left leg 
ligatured but so as to exclude the sciatic nerve. 
237 p.m., -25 ce, of a 1% solution of Pseudechis venom injected 
into dorsal lymph sac. 
320 ., both legs kicked when foot was pinched. 
areata 
Oe iatectere a 
