ARTIFICIAL PARTHENOGENESIS 573 



black), which accelerates certain chemical reactions by the condensation 

 of the reacting substances on the surface of the platinum, and their 

 consequent increase in concentration. This process of condensation on 

 surfaces is called adsorption. Warburg supposes that the oxidizing en- 

 zymes, oxidizable substances and oxygen are condensed on "surfaces," 

 thus causing the oxidation rate to increase, but what surfaces he means 

 it is difficult to determine, in some places apparently referring to sur- 

 faces of granules or colloidal particles, in others to cell or nuclear 

 surfaces. 



The adsorption of easily adsorbed substances may retard or prevent 

 entirely the adsorption of others less readily adsorbed. Warburg found 

 that anesthetics reduced the respiration of a mass of cell granules, pre- 

 sumably by driving the enzymes or oxidizable substances from their 

 surfaces. He further observed that animal charcoal in water oxidized 

 oxalic acid to COo, whereas if anesthetics were added the oxidation was 

 reduced. 



Warburg and Meyerhof found that the respiration of sea-urchins' 

 eggs was not entirely destroyed by grinding with sand, presumably be- 

 cause the cell granules were left intact. They explain it, however, as 

 an auto-oxidation or spontaneous oxidation of lecithin in the presence 

 of iron salts, the oxidation taking place in the test tube. Warbu^-g 

 found iron and lecithin in the sea-urchin eggs and observed that if the 

 total lecithin that could be extracted from a mass of eggs were mixed 

 with a dilute solution of iron chloride, the oxidation was as great as 

 that of the mass of ground cells. From his data we conclude that the 

 mass of ground unfertilized eggs undergoes the same oxidation as does 

 the same mass of cells if it were fertilized before grinding. Warburg 

 interprets this as indicating that the oxidation of unfertilized eggs is 

 due to auto-oxidation of lecithin, and that the increase in oxidation on 

 fertilization is due to increase in structure (surfaces). Since mechan- 

 ical agitations, however, may cause the eggs to develop, it is possible 

 that the grinding first stimulated each egg to as great respiration as 

 that of a fertilized egg, but the crushing and subsequent mixing of sub- 

 stances reduced the oxidation. It is interesting to note that, whereas 

 unfertilized as well as fertilized eggs absorb oxygen and give off CO,, 

 ground eggs or lecithin and iron mixtures do not give off COo, indi- 

 cating oxidation is not complete. 



Eelation" of Oxidation" to Permeability 



E, Lillie supposed the oxidation within the unfertilized eggs 

 to be suppressed by an accumulation of some end product of oxidation 

 that could not escape. It is possible that such a substance might act 

 like an anesthetic and suppress oxidation by adsorption to the granules. 

 Lillie supposed this substance to be carbonic acid, but this is hard to 



