250 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 



which had been dipped into fluid only once for the whole, the time occupied in 

 touching them being about five seconds. Each of these eggs became fertilized, and 

 segmentation commenced in two of them in exactly Jive hours, and in the remaining 

 four in from three to four minutes later. The period at which segmentation com- 

 menced having been very carefully watched, and the whole of the eggs having been 

 submitted, during the interval, to the same physical conditions of heat, light, quantity 

 of water and degree of aeration, the result, in regard to the difference of time at 

 which they began to change, seemed to be accounted for only on the assumption 

 that it was due to a greater quantity of influence applied to the first two than to the 

 others ; and this opinion has since been more fully borne out by other experiments. 

 The fluid at the time it was employed had been thirty-five minutes mixed with 

 water. On ihejifth day each of these eggs was producing an embryo. 



Three eggs were placed in separate cells, and each egg was touched once with the 

 pin-head loaded only once for the three, the fluid employed having been twenty-three 

 minutes mixed with water. After four hours and forty minutes two of these eggs were 

 undergoing segmentation, and on the fifth day both were producing embryos. The 

 third egg was not impregnated. 



Twenty-two eggs, in a large cell, were each touched once with the pin-head loaded 

 for each egg when the fluid had been one hour and forty-seven minutes mixed with 

 water. Some of the eggs in this experiment were touched on the white surface, 

 others on the dark, and others at the side, or about midway between the white and 

 dark surfaces. 



In the same cell with these eggs, but at a little distance from them, were placed 

 eighteen other eggs, which were not touched with the pin-head, but were simply 

 allowed to remain in the same cells with the twenty-two eggs experimented on, and 

 the cell was then filled with pure water. At the end of four Jiours and Jifty minutes 

 the chamber had been formed, and segmentation had commenced in each of the 

 twenty-two eggs experimented on. But in addition to these there were also two of 

 the eighteen g which had not been experimented on undergoing segmentation. 

 These, during the expansion of their envelopes, had come into contact with some of 

 the fecundated eggs, and had also become fecundated by some of the spermatozoa 

 which had been supplied to them. Five days afterwards the whole of these twenty- 

 four eggs were producing embryos ! so that not only had the quantity of spermatozoa 

 employed been fully sufficient to fecundate the eggs actually touched, but also others 

 present in the same water with them. 



In another experiment, made before the preceding, but with some of the same brood 

 of eggs and same sample of fluid, I placed five eggs in a cell, and touched each once, 

 very lightly, with the pin's head loaded once only for the whole. This was when the 

 fluid had been only eighteen minutes mixed with water. The object of this experi- 

 ment was to learn whether there is any difference in the result when the eggs are 

 touched at different parts of their surface. Accordingly the trial was made by touch- 



