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Chrysemys picta Schneider, a fresh water turtle, is capable of withstanding lengthy periods of fasting and cold torpor. An investigation was made of the biochemical differences between specimens in cold torpor, 4° ± 2°C, for 4–8 weeks, fasting specimens at room temperature, 22° ± 4°C, for 6–8 weeks and fed controls at the same room temperatures. Respiratory quotients of controls, torpid and fasting turtles were: 0.814 ± 0.019, 0.744 ± 0.029, 0.719 ± 0.025. The specimens in cold torpor showed marked decreases in oxygen consumption, heat production and metabolic rate. The fasted turtles showed characteristic biochemical properties of decreased liver total fatty acids, decreased blood glucose, and increased urine uric acid levels. The specimens in cold torpor had increased liver total fatty acids, a significant increase in liver glycogenolysis and increased urine uric acid levels. It was concluded that fundamental metabolic and biochemical differences exist between turtles in cold torpor and fasting turtles, and that both experimental types differ from the fed controls.

This program deals, on the whole, with the changes which talze place in aqueous media, mostly solutions, when their temperature is lowered and raised at various rates to various end points. Particular emphasis is placed on the effects of rapid cooling to very low temperatures in conditio s under which a stable equilibrium cannot be reached, and on th effects of a relatively slow rewarming during which the equilibriumlis reestablished. The information obtained can be classified into three categories: (1) methods, (2) changes observed, (3) special problems; these are presented in three sections in the table of contents below. The findings were published in 9 papers (some 125 pages) and in 7 abstracts of communications.made at meetings of the Society for Cryobiology, the Biophysical Society and the American Physiolog-ia. Society. The papers (numbered 1 to 9) and the abstracts (numbered Al to A7) are listed hereafter and the subject-matter treated is indicated in the table of contents by the numbers in the columns on the right side.

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