While the work done in the nervous system is no less important than that done in the muscular system, it seems to require a very much smaller oxidation of food materials. However, a certain amount of this oxidation always accompanies nervous activity. The food materials are conducted to the nervous system by way of the blood-vessels, and during periods of rest they are stored up in the nerve cells in granular form. These granules stored up during periods of rest represent concentrated nerve foods and are without doubt the result of anabolic processes. During periods of activity these condensed foods are oxidized, the products of oxidation being carried away into the blood and lymph. Incident to this oxidation, there is liberated as a primary and essential result the nervous energy so closely analogous to electrical energy, together with a certain amount of heat. The products of combustion are, so far as known, similar to those for the muscle tissue, and they follow a similar course in their preparation for excretion.