NINE FIGURES
Kalmus ( '28 a) and Howland and Bernstein ( '31) have made direct measurements of the oxygen consumption of single cells of Paramecium caudatum. Kalmus ( '28 b) used his instrument for an investigation of certain variables affecting the respiration of P. caudatum. He reported a decrease in the rate of oxygen consumption with decrease in partial pressure of oxygen, an observation in disagreement with the work of Amberson ('28) and Lund ('18a), both of whom used large numbers of organisms.
Howland and Bernstein ('31) reported that in their work with the Kalmus respirometer they observed a volume decrease regardless of the presence or absence of an organism in the respirometer, and they attributed this to a failure of the Kalmus technique to assure adequate temperature equilibrium. With a modified device of their own they found values for the rate of oxygen consumption of single cells of P. caudatum which were about one-tenth of those reported by Kalmus. Curiously enough, however, the values reported by Kalnius agree well with those which Ludwig ('28) regarded as being most probable of the values available at that time. They are also in good agreement with values recently found by the present authors using a new type of differential respirometer (Cunningham and Kirk, '41).
The respiration of Paramecium is reported to be subject to a number of influences, including (1) the nutritional state of the cell (Leichsenring, '25, and Lund, '18 b) ; (2) the presence or absence of conjugation (Zweibaum, '31), and (3) the partial pressure of the oxygen (Kalmus, '28 b). The effect of (1) is reported to be marked, an increase of 300% being observed when starved cells are fed (Lund, '18 b). (2) Is reported to increase the oxygen consumption by 350% when it is occurring.
According to Kalmus, (3) will result in a decrease of 3576 when the 'Aided by grants from the Research Board of the University of California.