EFrrect oF ARTIFICIAL MEMBRANE FORMATION 75 
When the disintegration has once commenced, it continues 
until, after a certain time which varies inversely with the 
temperature, the whole egg is disintegrated. Fig. 23 represents 
an egg a few hours after artificial membrane formation, in 
Fig. 25 Fig. 26 
Fries. 23-26.—Disintegration of the sea-urchin egg after artificial membrane 
formation, if it is not submitted to treatment with a hypertonic solution or an 
inhibition of oxidations. 
which the nuclear spindle is visible. It did not develop farther, 
but a little later a few clear drops (Fig. 24), resembling polar 
bodies, appeared to exude from the egg; I suspect that this 
extravasation of drops took place in the equatorial plane. This 
disintegration then proceeds farther (Fig. 25), until finally the 
egg is almost completely destroyed (Fig. 26). 
