1892.] Experimental Embryology. 587 
PINs > ori oe et Re for 5 minutes 
GOE e sc Soe ii for a NGA for 5 minutes 
WOR s,Q ee Seto eee 2% for 12 minutes 
Bene oor ire ae 31°C. for 10 minutes 
STRONG REAGENTS. 
PAIN E wht ante see be phic tigtr R 9 SOR 
SEVOODING co ke cw hel ws OLS for: 20 minutes 
MODRE e 000 tay Janie wants dh <i aint AN. Tor -5 hours 
ONIN e ea i 5 te es a arg asda, (ae ee A S manuto 
Monino n eai py py kash sto cae tO (hone 
Cora a a ae a ee eS bori 
SRO co wih ered ae cate a sk ale Ne kOe A, minios 
These do not all act alike; quinine, chloral and probably 
cocaine and overheating temporarily stops the movement of 
the sperm, a diminution in size of the fertilization elevations 
upon the egg, postpone cleavage one-half to one and one-half 
hours, interrupt cleavage of nucleus, sometimes making it 
take retrograde steps, and interfere with formation of rays 
within the protoplasm of the egg. 
Nicotine and strychnine, on the other hand, seem to increase 
the activity of the sperm and the contractility of the egg pro- 
toplasm. Morphine appears to have an intermediate action. 
The authors explain the occurrence of polyspermy after the 
_action of these agents as being due to the lack of normal sen- 
sitiveness on the part of the ovum. For normally the entrance 
of one sperm causes the egg to throw off a membrane which 
prevents the entrance of others, a membrane which is seen to 
be formed even upon fragments of eggs shaken loose before 
cleavage, yet when acted upon by these drugs the protoplasm 
of the egg is not sufficiently stimulated to form a membrane 
until several sperms have entered. 
The internal fertilization, fusion of male and female nuclei, 
may be also retarded as much as one hour, and various unusual 
phenomena introduced in connection with the supernumerary 
sperms, without necessarily preventing the ultimate develop- 
ment of the oosperm. 
