222 MR. NEWPORT ON THE IMPREGNATION OF 



But there were several eggs that appeared to have been partially impregnated, the 

 whole of which were abortive. Partial impregnation, as before stated, is shown in a 

 very imperfect cleavage of the yelk, sometimes on one surface only, and sometimes 

 complete as regards one half of the yelk, but imperfect or irregular in the other. 



No. 8. Forty-two ova from the last experiment, No. 7, were removed from the car- 

 mine at the end of thirty seconds, and were immediately well washed to get rid of the 

 adhering spermatozoa and granules of colouring matter. Not one of these ova pro- 

 duced an embryo, but several had become partially impregnated. 



These experiments were made in the middle of March, when the season was un- 

 usually cold, and the mean lowest temperature of the room during twelve days 

 was only 43 FAHR., and the mean highest 47 FAHR. ; at a higher temperature the 

 results, I have little doubt, would have been more favourable. The eggs had been 

 impregnated however when the temperature, during the first twelve hours, was 55 

 FAHR., so that the question respecting the infiltration of solid matter with the water 

 absorbed by the envelopes of the eggs was not affected. 



About four hundred and twenty eggs were employed in this set of experiments ; yet I 

 could not detect any granules of the colouring matter of carmine held in suspension, 

 and of dimensions equal to those of the spermatozoa, which had passed into the tissue 

 of the envelopes of the eggs, although they had become tinged by the colouring matter 

 in combination with the water. Abundance of granules of colouring matter of most 

 minute size, and not more than one-third the diameter of the spermatozoa of the 

 Frog seen beside them, adhered to the surface of the envelopes, and it was to these 

 chiefly that the red colour of the whole was due. Every part of the envelope exhi- 

 bited the same uniform appearance, the granules being pretty equally distributed over 

 the surface, and the suffusion of colour was uniform in the interior. These facts ap- 

 peared to be conclusive with reference to the question of the presumed existence of a 

 fissure or perforation through the coverings of the egg of the Frog before, or at the 

 moment of fecundation, as is supposed to exist in the ovum of the Rabbit. I have 

 not been able to detect any appearance of orifice or fissure in the egg of the Frog- 

 envelopes, and the course of which, if such really exists, would no doubt be indicated 

 by some deposition of the colouring matter of the carmine, to a greater or less ex- 

 tent, in its tract. The result of these experiments was thus most unfavourable to the 

 belief that the spermatozoa penetrate bodily through the membranes of the ovum ; 

 and to that of the supposed existence of a special opening in these membranes for 

 their admission. 



I ought now, however, to mention one experiment that seemed to favour the opi- 

 nion that the spermatozoon enters the ovum. I had taken several ova, together with 

 the oviducts into which they had passed, from the body of a Lissotritonpalmipes, and 

 others from that of Triton palustris, for the purpose of artificial impregnation. Some 

 of these I pressed from the oviducts into a very clear solution of carmine, taken from 

 a solution which had remained undisturbed for nearly a fortnight, so that the granules 



