OF THE BAEK OF EE YTHEO PHLEU M GUINENSE. 
655 
when the irritation is applied to the muscle itself, and it probably does not increase it ; 
for although apparently positive results were attained on the first occasion when the lifting- 
power was experimented on, these results were not borne out by further experiments. 
4. The muscle-curve given by a nerve-muscle preparation taken from a frog poisoned 
by a large dose of casca appears to be quite a normal one. 
5. It also exerts no action on the sensibility of muscle to electrical stimulation if this 
sensibility be tried quantitatively by estimating the weakest interrupted current which 
will produce a contraction. 
From all these results, then, it may be concluded that while the drug produces a 
peculiar and characteristic change on muscular tissue immersed in it for some days, it 
is not a muscle-paralyzer. 
Action on Motor Nerves. 
If casca had any paralyzing action on the ends of motor nerves similar to that of 
curare it would be found that after immersion in a solution of the drug the muscle 
would respond to electrical stimuli directly applied to it, but not to those applied to 
the nerve. In Experiment LII., however, the nerve also is seen to preserve its irri- 
tability, and therefore we may conclude that casca has no action on motor nerves. 
Action on Sensory Nerves. 
Effect on Reflex Excitability. 
Experiment LII.— March 22. 
The cerebrum of a living frog of medium size was destroyed. The circulation through 
the left leg was cut off by ligaturing the arterial trunks above the knee ( vide fig.). The 
sciatic nerve was left uninjured. | cub. centim. of the alcoholic extract was then 
injected beneath the skin of the back. 
