In scorbutic guinea pigs fed an ascorbic acid-deficient diet for 18 days, the ascorbic acid contents of the liver and plasma were less than 4% those of the control animals, while the content in the brain was about one-third that of the controls. In normal animals, the concentration of ascorbic acid was highest (7.55±1.46μg of ascorbic acid/mg protein) in the S₃ fraction and was also fairly high (5.37±0.91) in the P_2p fraction (cytoplasm of nerve terminals). During ascorbic acid deficiency, the contents in the P_2p and microsome fractions decreased slightly faster than those in other fractions. Even after 18 days' deficiency, no significant change was found in the acetylcholine content of the brain.