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 maturity. 



No. 3. One hundred and sixty eggs horn 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 eggs were passed from a Frog which had been killed forty-four 

 hours before, the temperature of the atmosphere during this period having risen from 

 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, 

 shrivelled, and irregular, as if they had been affected by the solution of potass, or 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 interesting, from 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 that 

 the influence of the spermatozoon on the yelk, whatever may be its precise nature, 

 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 



