Page:Life in Motion.djvu/120

The other muscle does not respond because its nerve, poisoned by curare, is practically dead, or at all events it cannot act on the muscle. By the curare we have poisoned every nerve filament and every end-plate in this muscle, but we left the muscle-substance just as if we Fig. 53.—Diagram showing the arrangement of the apparatus in demonstrating by curare the inherent irritability of muscle. b, galvanic element; p primary and s secondary coil of induction machine; k, key for admitting shocks either to nerves or muscles; k′, double key for sending shocks either to the two muscles, m and m′, or to the two nerves, n and n′; t t′ telegraph signals. The arrows show the direction of the currents. had dissected out and removed all the nervous structures. Now I send the shocks to both muscles, and you notice that both telegraph signals are raised, apprising us that both muscles have contracted. The muscle-substance then contracts when directly stimulated