ON THE ENERGETICS OF DIFFERENTIATION. VII

Abstract

The O2 consumption of artificially activated eggs of U. caupo was followed manometrically. Regardless of whether or not the treatment results in cleavage, the initial rate is the same as that of the normally fertilized controls. The rate then rises with time, but much more slowly than in the fertilized eggs. The increase in resp. rate with time is greater with cleaving than with non-cleaving parthenogenetic eggs. Measurements were also made of the resp. of fertilized eggs in phenylurethane. With a concn. of phenylurethane giving inhibition of cytoplasmic division and retardation of nuclear division, the initial rate of O2 consumption is the same as that of the controls, but the rise in rate with time is retarded. The delayed rise in respiration of the parthenogenetic and the phenylurethane-treated eggs is apparently linked with their slower development.