ACTIVATION OF THE Eaa By BASES 149 
in 0.3c.c. N/10 HN,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 tetraethylammoniumhydroxide, a longer exposure is neces- 
sary than with the weak base HN,OH. This is in analogy with 
our experience with acids (see preceding chapter). 
Not only NH,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 
+CaCl,+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 twenty to 
twenty-five minutes at 26°C.) into any hypertonic solution, 
e.g., 50 c.c. sea-water + 8 c.c. 24m 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 + 40 ¢.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,OH caused artificial parthenogenesis much 
more quickly than the strong bases NaOH or tetraethylam- 
moniumhydroxide. The amines were more effective than 
NH,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 
