. Chemical embryology. Embryology. 638 THE RESPIRATION AND [PT. Ill the male and female pronucleus takes place later on there is no fresh rise in the process, but rather a further slowing down. This is illus- trated by Fig. 11 o, which shows an experiment covering a longer period. At the 25-minute point, where the nuclei fuse, there is no kink in the curve, and the process is slowing off. "The nuclear features of syngamy", as Shearer puts it, "seem connected in no direct way with the oxidations taking place in the ovum," Such a conclusion is in agreement with the work of Wa
. Chemical embryology. Embryology. 638 THE RESPIRATION AND [PT. Ill the male and female pronucleus takes place later on there is no fresh rise in the process, but rather a further slowing down. This is illus- trated by Fig. 11 o, which shows an experiment covering a longer period. At the 25-minute point, where the nuclei fuse, there is no kink in the curve, and the process is slowing off. "The nuclear features of syngamy", as Shearer puts it, "seem connected in no direct way with the oxidations taking place in the ovum," Such a conclusion is in agreement with the work of Warburg, which, as we have already seen, led to the view that the surface of the egg was of particular importance with regard to the oxidations proceeding in it, and hence the respiratory rate. Injury to the egg-membrane is invariably followed by a great increase of oxygen consumption of echino- derm eggs, and, as will be noted presently, Meyerhof found that similar treatment was accom- panied by a definite increase in heat production. In eggs treated with hypotonic sodium chloride solutions, the absence of calcium and potassium ions interferes with the normal con- dition of the cell-wall, and the oxygen consumption rises to five or six times the normal. In just the same way the heat production rises from o-g to 3-4 gm. cal. per hour after treatment with valerianic acid, which induces artificial membrane formation. There is as yet no satisfactory explanation for these phenomena, for the most recent knowledge which has accumulated about oxidation processes can hardly allow us to be satisfied with the simple concep- tion of an accumulation of iron in the surface layer of the egg, as Warburg suggested. Even if it were there, and were released in some way by parthenogenetic agents, it does not, as is now known, catalyse all types of oxidation. However, Runnstrom's work has shown that the rise in metabolic rate which occurs at fertilisation is connected both with the colloidal state o
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