144 ARtTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
sea-water that contains benzol; but if HCl is added to this 
sea-water, this membrane formation does not take place.! 
If the eggs are transferred from the butyric acid solution, 
not into sea-water, but into a neutral mixture of N aCl, KCI, and 
CaCl,, often no proper membrane is formed. But if the eggs 
are put into an alkaline mixture of NaCl, KCl, and CaCl, 
proper membranes are formed by the egg. 
The experiments, however, lead to still another unexpected 
result. If the eggs are transferred from the acid solution into 
the neutral mixture of NaCl, KCl, and CaCl, they neither 
develop nor disintegrate. They appear rather to return into 
the resting condition in which they can be fertilized with sperm. 
I have fertilized such eggs with sperm even after two days, 
and could evoke development. 
The following experiment also shows that such eggs remain 
in the resting condition if they are transferred from the acid 
solution to the neutral mixture of NaCl, KCl, and CaCl. 
If the eggs are placed, after treatment with the fatty acid, in 
sea-water or in an alkaline solution of NaCi, KCl, and CaCl, 
(in which they form a perfect membrane), a further short treat- 
ment with a neutral hypertonic solution is sufficient to cause 
all the eggs to develop into larvae. In such an experiment it 
was only necessary to leave the eggs from 20 to 50 minutes in 
a neutral hypertonic solution (50 ¢.c. NaCl+2.2 c.e. KCI+ 
1.5 ec. CaCl, all m/2, +9 ¢.c. 22 m NaCi), to cause all the 
eggs to develop into larvae. The eggs, however, which had 
been transferred from the acid solution into the neutral solu- 
tion of NaCl, KCl, and CaCl, could generally not be made to 
develop even by 120 minutes’ exposure to the neutral hyper- 
tonic solution. This again shows that these eggs were really 
in the resting condition. These facts are a new proof for the 
statement made in a previous chapter, that the acid causes the 
development of the egg only indirectly through the membrane 
formation. 
1 Loeb, op. cit. 
