244 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 
pet-ature which is always most favourable to fecundation, there were no s^ns that any 
change had even been commenced in those eggs which had been immersed for a onger 
period than thirty-five minutes. But it must be borne in mind that the fluid employed 
Ld been thirty-five minutes mixed with water, and consequently had begun to lose 
some of its efficacy. The results of the corresponding experiments at the lower tem- 
perature-Atmosphere 55”, Water 63°-were similar, but less marked. 
On comparing the two sets of investigations, it was found that no evidence o 
fecundation occurred in either of them, when the eggs had been immersed during 
forty-five minutes before the impregnating fluid was supplied to them ; and that only 
the very earliest symptoms of any influence having been communicated to 
after thirty-five minutes’ immersion, occurred in those which were submitted to the 
higher temperature, in the irregular contraction of the yelks ; while in each set, bo ^ 
in the higher and lower temperature, some of the eggs, after twenty-five “ 
immersion, showed unequivocal signs of partial fecundation m the formation of the 
respiratory chamber, the result of the contraction and depression of the uppei porbon 
of the yelk previous to segmentation. But in both sets there were some eggs which, 
after fifteen minutes’ immersion, had become fecundated, and produced einbiyos. 
The relative number of embryos produced after immersion for this and shorter spaces 
of time was certainly greatest in the higher temperature ; since when the total 
number of eggs employed in the last six experiments iii each of the two sets, ii. 
which only any embryos were produced, were compared with the number of embi jos, 
it was found that in the higher temperature there were seventy-eight embryos from 
five hundred and thirty-six eggs; while in the lower temperature, from six hundred 
and two eggs, there were only seventy-six embryos. 
The period at which segmentation occurred in the fecundated eggs o t e two se - 
corresponded also with the above results. In most of the eggs fecundated m the lug er 
temperature segmentation commenced about ten minutes earlier than in those which 
had been fecundated, and remained during the first hour in ^ 
These results seem to show, that while the eggs are more rapidly affected, they 
also more certainly impregnated, and the embryos produced in greater numbers ar 
a higher than at a lower temperature. But it must be borne in mind that the number 
of eLs fecundated in these experiments can only be regarded as conipaiative, an. 
as iere approximations to what takes place in a state of nature, t be experuiieuts 
having bera made with fluid which had been removed from the body and coi - 
siderably diluted with water, more than half an hour before it was employed, and 
consequently when its efficacy had been considerably diminished. 
These facts, then, go to confirm the previous conclusions, that the organic foice o 
vitality of the spermatozoon is of shorter duration than that of the egg ; since, it the 
results of these experiments be compared with, those obtained from former ones. ' 
will be seen that the insusceptibility of the egg depends very much more on he 
endosmic action of its envelopes after immersion in water, than on any loss of vitality . 
