Metabolism of the Black Snake Embryo

Bohr (1904) reported CO2 production of an embryo of Natrix natrix, weighing 0-46 g., to be 120 mm./g./hr. at 14-2° C ; the CO2 produced at 28 0 C. was 3 times that at 15 C , and production by a newly hatched snake at 15° C. was approximately 90 mm./g./hr. Other data are given, but they are not related to stage of development, and oxygen utilization was not measured. Zarrow & Pomerat (1937) made rather exhaustive studies of the effect of temperature on various aspects of respiratory behaviour of the smooth green snake during the last week of development. It appeared profitable, therefore, to obtain details of respiratory exchange throughout the developmental period of snake embryos. Such data were available from the same embryos which served for the excretion studies reported elsewhere in this Journal by the author (1953).