236 MR. NEWPORT ON THE IMPREGNATION OF 



rapid as in the artificial impregnation, R 5 (p. 23 1 ), in which it took place in four hours 

 and thirteen minutes. On the eighth day twelve embryos had been produced. 



These facts seemed to show, precisely as in experiments with solutions of potass, 

 that impregnation is commenced very quickly; and further, that it was not arrested 

 by the gum when applied only two seconds after the spermatozoa, but that the change 

 proceeds almost as uninterruptedly as in a perfectly natural impregnation, since 

 the number of embryos was almost as great as in No. 5 R, seeing that the fluid 

 employed had been obtained and mixed with water one hour and thirty-four minutes. 



No. 6. P.M. 3 h 22 m . Seventy ova, passed on a moistened surface, were bathed with 

 a thick solution of gum, and two seconds afterwards with some of the impregnating 

 fluid employed in the last experiment, and water was then added ; the whole time 

 occupied, as above, being only twenty seconds. 



This experiment was the converse of the preceding. At four hours and twenty-eight 

 minutes only one egg out of the whole had become segmented ; but others gave signs 

 of being about to change, and some hours later a few had done so, but there were not 

 at most more than ten. At the end of the seventh day two embryos had been produced. 



Thus while a comparison of these two experiments seems to show that the gum acts 

 simply as a mechanical obstruction to the process of fecundation, this experiment, 

 No.6, when compared with Nos. 1 to 4, made at eleven degrees lower temperature, shows 

 also the influence of a higher degree of temperature in accelerating fecundation. 



The two following experiments were made with a view to test the efficiency of the 

 fluid and ova employed, now at one hour and fifty minutes after the fluid had been 

 obtained : when examined at this time with the microscope, there were still an abun- 

 dance of active spermatozoa. 



No. 7- P-M. 3 h 41 m . Eighty-Jive ova were accordingly placed in water with some 

 of the impregnating fluid and allowed to remain to test its efficacy. 



At four hours and twenty-four minutes nearly the whole of the ova had become seg- 

 mented, and on the seventh day forty-two embryos had been produced. 



No. 8. P.M. 5 h 50 m . One hundred and thirty-two ova were now passed into the re- 

 mainder of the impregnating fluid, which had at this time been four hours mixed with 

 water. 



When examined at the end of five hours and ten minutes, not a single specimen 

 had become impregnated. This was proved by the result, that at the end of seven 

 days not a single embryo had been formed. The fluid had thus lost its fecundating 

 property at the end of four hours in a temperature of 60 FAHR. 



No. 9. April 6, 1850. Atmosphere 60 FAHR. 



P.M. l h 50 m . One more experiment was now made with the gum solution, for the 

 purpose of comparing it with the following experiments with starch. 



One hundred and twenty-two ova were passed on a dry surface and covered with a 

 thick solution of gum, and three seconds afterwards with impregnating fluid that had 

 been mixed with water only thirty minutes. The time occupied was not noted, but 

 fresh water was added to the ova at the end of fourteen minutes. 



