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.