1907.] Torelle, Fertilization of Eggs of Asterias and Arbacia. 123 
A 5 % ether solution produces inactivity in active spermatozoa ; 
their activity is increased in .5% and 1% sohitions. 
Eggs fertihzed by spermatozoa immersed in .5% and T% ether 
solutions develop more rapidly, and the embryos are more active 
than those produced by normal fertilization. The rate of develop- 
ment is increased by an immersion before fertilization of the 
spermatozoa for several minutes, instead of one minute in the 
.5% and 1% ether solutions. 
In most of the experiments, when the spermatozoa were 
immersed in 5% ether for one or for ten minutes, and then added 
to eggs in sea-water, division of the eggs did not take place. 
An immersion of spermatozoa in the ammonium hydroxide 
solutions used, stronger than .001% produces inactivity in the 
spermatozoa ; only a few eggs divide after such spermatozoa have 
been added to them, and the eggs which divide do not survive the 
first few cleavages. A large precentage of eggs divide after fertili- 
zation of spermatozoa, which have been immersed in .001% of 
ammonium hydroxide, but do not reach the gastrula stage. 
In Asterias, no eggs divide when spermatozoa are added to 
them after an immersion of twenty minutes in solutions of alcohol, 
ranging from 5% to 12%. 
Eggs of Asterias divide when spermatozoa are added to them 
after an immersion of ten minutes in 5% to 8% solutions of 
alcohol ; when spermatozoa are immersed for one minute only in 
solutions ranging from 5% to 11%, division occurs in the eggs 
to which they are added. 
Abnormal division and development follows the fertilization 
of eggs by sperm immersed in 10% to 12% alcohol solutions, and 
by sperm immersed in 2% to 4% ether solutions. 
CONCLUSIONS. 
The entire series of experiments show: 
I. That inactive (immature?) spermatozoa can be made 
