262 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
This results in the extrusion of the polar bodies and develop- 
ment. But the effect of the alkaline solution is enhanced by 
the treatment of the eggs with hypertonic sea-water. 
3. We have already stated that the weak bases. are much 
more efficient in causing artificial parthenogenesis than the 
strong bases. The best effects were produced with the amines, 
especially butylamine and benzylamine; next in efficiency were 
NH,OH and trimethylamine, and the weakest effects were pro- 
duced by the strong bases NaOH and tetraethylammonium- 
hydroxide. 
To give an example: to 50 c.c. hypertonic sea-water (100 c.c. 
sea-water+18 c.c. 2! m NaCl) were added 1.5 c.c. N/10 
NaOH, benzylamine, and NH,OH8, respectively. Of the eggs 
that had been forty-five minutes in benzylamine, 40 per cent 
developed; the same result was produced by an exposure in 
NH,OH of 80 minutes. An exposure of 115 minutes in NaOH 
gave a much smaller number of larvae. Those treated with 
NaOH reached the swimming stage as a rule much later than 
those treated with anamine. The eggs treated with the amine, 
especially with butylamine and benzylamine, segmented almost 
normally, although much more slowly than the eggs fertilized 
with sperm. 
In repeating these experiments with sea-water made alkaline 
(but not hypertonic), the writer was struck with the fact 
that the eggs developed into larvae without segmentation, and 
very slowly, while with both hypertonic and hyperalkaline 
sea-water they segmented and developed more rapidly into 
larvae, though still more slowly than the eggs fertilized by sperm. 
It is obvious that when the hypertonic solution acts in this 
way it makes the development more normal. This may also 
be a “second factor” effect. While the eggs of Polynoe do 
not directly disintegrate after artificial membrane formation, 
they show their abnormal state by developing without segmen- 
tation. The hypertonic solution remedies this defect, without, 
