THE SELECTIVE ACTION OF NICOTINE ON THE CENTRAL NERVOUS SYSTEM OF THE SQUID, LOLIGO PEALII.

1. In specimens of freshly hatched squid, Loligo pealii, nicotine acts upon the cerebral ganglia alone. 2. After 1 minute in the nicotine solution 1:500,000, the latent period for the mantle spasm is independent of the time spent in the solution. 3. The mantle spasm is conditioned by a chemical reaction, since the temperature coefficient of the process has a magnitude of about 2.8. 4. The velocity of the process which brings about the mantle spasm varies as the cube root of the concentration of the nicotine.