ACTIVATION OF THE EGG BY BASES 149 



in 0.3 c.c. N/10 HN 4 OH developed into larvae, while only very 

 few eggs developed that had been treated with the two strong- 

 bases. In order to cause artificial parthenogenesis with NaOH 

 or tetraethylamrnoniumhydroxide, a longer exposure is neces- 

 sary than with the weak base HN 4 OH. This is in analogy with 

 our experience with acids (see preceding chapter). 



Not only NH 4 OH but other weak bases like the amines, 

 e.g., butylamine or benzylamine, are effective. It is of great 

 interest that the weak base protamine prepared from the 

 sperm of the salmon is one of the most efficient substances for 

 the causation of artificial parthenogenesis. These experiments 

 were made on the eggs of Arbacia. An exposure of the eggs 

 for only five minutes to a solution of 50 c.c. m/2 NaCl+KCl 

 -fCaCl 2 H-0.3 c.c. of a N/10 solution of one of these weak bases 

 suffices to induce development in the egg of Arbacia. If the 

 eggs are put afterward for the proper time (about tw r enty to 

 twenty-five minutes at 26 C.) into any hypertonic solution, 

 e.g., 50 c.c. sea-water -+- 8 c.c. 2fm NaCl; or into sea-water 

 whose concentration had been raised to the same degree by 

 evaporation; or into a mixture of 10 c.c. sea-water -f- 40 c.c. m 

 solution of cane sugar, a certain percentage will develop into 

 plutei after they are transferred into sea-water. 



These results were confirmed in experiments on an annelid 

 (Polynoe) of the Pacific coast. It was found that the weak 

 bases like amines (methyl-, ethyl-, butyl-, and benzylamine 

 were tried) and NH 4 OH caused artificial parthenogenesis much 

 more quickly than the strong bases NaOH or tetraethylam- 

 moniumhydroxide. The amines were more effective than 

 NH 4 OH. 



The reason for this paradoxical behavior of the bases is the 

 same as for that of the acids; the weaker bases are more efficient 

 than the stronger for the reason that the weaker bases diffuse 

 rapidly into the egg while the strong bases do not diffuse at all 

 into the egg or only to a very slight extent. The direct proof 



