242 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 
No. 2. Seventy-three eggs were taken from a Frog which had been killed about 
thirty hours, and were bathed with fluid which had been one hour and twenty minutes 
mixed with water. 
At the end of six hours several of these eggs had become irregular, but one had 
certainly been fecundated, as one embryo afterwards came to matuiity. 
No. 3. One hundred and sixty e^g^from the Frog which supplied those employed in 
the experiment No. 2, were bathed with fluid from another male, immediately after 
it had been obtained, but not a single egg was impregnated. 
No. 4. Thirty-seven eggswQve passed from a Frog which had been killed /orfg^owr 
hours before, the temperature of the atmosphere during this period having risen fiom 
50° Fahr. to 55° Fahr. These eggs were bathed with fluid which had been obtained 
about three quarters of an hour. At the end of six hours I found, to my surprise, that 
one egg had become segmented, but that the yelks of the others were flattened, 
shrivelied, and irregular, as if they had been affected by the solution of potass, oi by 
decomposing seminal fluid. On the seventh day the egg which had been segmented 
had produced an embryo. 
From these results, then, it appears that while the spermatozoon at a mean tem- 
perature of the atmosphere of 55° Fahr. usually loses its vitality, and is inert in less 
than four hours, and but rarely is efficient at a longer period after immersion in 
water, the egg retains its reproductive property for a very much longer time, especially 
if not removed from the body of the dead animal, only losing it at twenty-four hours 
after the death of the parent, and occasionally retaining it for forty hours. 
The experiment No. 4, in which the latter fact is shown, is inteiesting, fiom the 
circumstance that the same results are produced by the living vibratile spermatozoon 
on the yelks of the dead eggs, as the majority of these were, as that which is occa- 
sioned by the application of dead and decomposing spermatozoa to the envelopes of 
the living one, as shown in No. 6 of the preceding set ; and further, that these results 
so closely resemble in appearance the first effects produced on the yelks of living eggs 
by the application of strong solution of potass ; thereby showing not only that powerful 
endosmic action takes place rapidly through the coverings of the egg, but also thai 
the influence of the spermatozoon on the yelk, whatever may be its precise natuie, 
is direct and immediate. 
4. ENDOSMOSIS OF THE EGG IN RELATION TO ITS VITALITY. 
It has before been shown that the endosmic action of the envelopes of the egg, on 
immersion in water, is closely connected with the act of fecundation ; and we have 
now further proof of this in the fact that the vitality of the egg may be preserved for 
many hours if the envelopes be not brought into contact with water ; so that the 
insusceptibility of the egg to become impregnated, after a lengthened period of 
immersion, is due to a diminution of the expansive property of the tissue of the 
