In 1905 the writer found that it is possible to induce artificial parthenogenesis (membrane formation) in the sea urchin by weak acids, such as the monobasic fatty acids or GOz, but not at all or only unsatisfactorily by the strong acids, such as HCl, HzS04, oxalic acid, and others. He suggested that this paradoxical behavior was due to the fact that only those acids which diffuse easily into the egg were able to cause membrane formation.' This assumption was supported by the observation that there existed an analogy between the relative physiological efficiency of various organic acids and their corresponding alcohols.
This paper intends to show that the weak base NH40H is much more efficient in the production of artificial parthenogenesis than the strong bases NaOH, KOH, and tetraaethy1ammoniumhydroxide. The writer found in 1907 that it is possible to substitute bases for acids in the process of artificial parthenogenesis with this difference, that the eggs had to be exposed to the alkaline solution for a considerably longer period than to the acid solution in order to cause them to develop.? The eggs of Strongylocentrotus could be caused to develop by putting them for nearly three hours into a mixture of 50 cc. m/2 (NaC1 + KC1 + CaC1,) + 0.5 or 1.0 cc. & NaOH. When such