ACTION OF THE HYPERTONIC SOLUTION * 109 
The larvae were crippled by too long an exposure. I also 
found that one could even obtain larvae if a trace of HCl was 
added to the hypertonic solution. I have not yet determined 
the lower limit of the concentration of hydroxylions in the 
hypertonic solution.! 
6. We will now proceed to the discussion of an apparent 
contradiction between the results of this and of the previous 
chapter. In the latter we saw that the eggs can be made to 
develop after membrane formation by keeping them for three 
hours or more in water that is poor in oxygen, or by preventing 
the oxidations by the addition of KCN. In this chapter we 
saw that the eggs after membrane formation can be made to 
develop by putting them afterward into hypertonic sea-water 
for some thirty to fifty minutes; but that this is only possible 
if the hypertonic sea-water contains a sufficient amount of free 
oxygen. How are these apparently contradictory statements to 
be reconciled ? 
The essence of the activation of the unfertilized egg con- 
sists in the production of membrane formation. This process 
is certainly not one of oxidation, since it can take place in the 
absence of oxygen or in the presence of KCN. Perhaps it 
depends ultimately upon a purely physical process (such as the 
liquefaction of a lipoid or the dissociation of a [hypot!.ctical] 
lipoid-protein combination). 
As soon as this process has taken place, development sets 
in in the egg. Why this is the case, we do not at present know. 
But at the same time this process leaves the egg in an abnormal 
or sickly condition. If the egg begins to develop while in this 
injured condition, it disintegrates. But if we prevent the 
egg from developing for some hours, by depriving it of oxygen, 
or stopping oxidations by the addition of KCN, the egg can 
develop normally. We must seek the reason for this in the 
1 Loeb, ‘‘Zur Analyse der osmotischen Entwicklungserregung unbefruchteter 
Seeigeleier,”’ Pfliiger’s Archiv, CX VIII, 197, 1907. 
