PROLONGATION OF THE LIFE OF THE EGG 91 
Ten per cent of the eggs had been transformed into ‘‘shadows”’ 
(white cytolysis). It goes without saying that all the eggs that 
had been in the aerated hypertonic sea-water five and a half 
hours were also dead. The eggs that had been in the same 
solution in the absence of oxygen appeared all normal when 
they were taken out of the solution, and three hours later— 
the temperature was only 15° C.—they were all, without excep- 
tion, in a perfectly normal two- or four-cell stage. The further 
development was also in most cases normal. They swam as 
larvae at the surface of the vessel and went on the third day 
(at the right time) inte a perfectly normal pluteus stage, after 
which their observation was discontinued. Of the eggs that 
had been five and a half hours in the hypertonic sea-water 
deprived of oxygen, about 90 per cent segmented.! 
In another experiment newly fertilized eggs of purpuratus 
were put into two dishes each containing 50 ¢.c. sea-water+ 
15 c.c. 2 m NaCl. To the one dish was added 1 c.c. 1/10 of 
1 per cent KCN. The eggs remained 305 minutes in the solu- 
tion. When they were put back into normal sea-water many of 
those that had been in the dish containing KCN developed per- 
fectly normally into plutei, while those that had been in the 
solution without KCN all disintegrated into droplets in about 
one-half hour. These experiments were often repeated and 
they are indeed very striking demonstration experiments. They 
show that the inhibition of oxidations in these experiments 
protects the egg against the injurious effects of the hypertonic 
solution for a considerable time. 
Chloral hydrate had also a very slight protective action. 
When 2.5 c.c. N/10 chioral hydrate were added to 68 c.c. of the 
hypertonic solution, about 5 per cent of the eggs were saved 
under conditions under which KCN saved all the eggs.” 
1 Loeb, University of California Publications, Physiology, III, 49, 1906. 
2 Loeb, ‘‘ Ueber die Hemmung der toxischen Wirkung hypertonischer Lésun- 
gen auf das Seeigelei durch Sauerstoffmangel und Cyankalium,’’ Pfliger’s Archiv, 
CXIII, 487, 1906. 
