220 MR. NEWPORT ON THE IMPREGNATION OF 



water they had been immersed in was coloured. I then again removed them to clear 

 water. At the end of sixteen hours they had parted with more colour, but were still 

 red, more especially between the inner portion of the envelope and the vitelline mem- 

 brane, and the water had again acquired a red hue, thus showing that both endos- 

 rnose and exosmose must have taken place. 



As it might fairly be objected that these ova, changed by immersion in spirit, were 

 unfitted for experiment, I made trial with others which had not been impregnated, 

 and being infertile, had remained in water many days without giving signs of decay. 

 When these were placed in the carmine solution, their envelopes became as deeply 

 and thoroughly imbued with colouring matter throughout their whole substance as 

 in the former ; and when placed in clear water they parted as readily with a portion 

 of it, so that it was evident that whenever the density of the fluid in which these 

 dead and infertile ova were immersed, was altered, a change by endosmose or exosmose 

 immediately took place in the fluid retained mechanically in their tissues. To this 

 cause, perhaps, may be ascribed the colouring of the ova in PREVOST and DUMAS'S 

 first experiment with ink, while other experiments, which I shall mention, made on 

 living and impregnated ova, lead me to regard the colour in the experiment with 

 frog's blood as merely the result of adhesion of colouring matter to the surface. 



The immediate objects I had now in view were, to learn whether impregnation is 

 effected by any direct and palpable infiltration of seminal matter through the enve- 

 lopes of the ovum ; whether the admixture of other matters with the seminal fluid 

 will prevent or arrest impregnation; and whether the spermatozoa collected on a 

 filter paper, and then placed with this in a fluid of great density, are as efficient as in 

 clear water. 



With these views, I prepared a very dense solution of carmine pigment in water, 

 and added parts of this to small quantities of water with ova, either before the 

 seminal fluid was mixed with the water, or immediately afterwards, and I expected 

 the results to show whether any solid particles, held in suspension in the fluid, passed 

 through the envelopes. The previous trials had shown that solid particles do pass 

 through the dead tissue, but it was doubtful whether the like result would occur in 

 the living. 



Carmine Experiments. Set O. March 13, 1850. Atmosphere 53 FAHR. 



No. 1. Eleven unimpregnated ova were passed into water mixed with carmine. 



The envelopes became as fully expanded, and imbibed fluid as freely as in the im- 

 pregnated ova, and acquired a red tint ; but much of the colour was due to the deposi- 

 tion of granules of matter on the surface, while I was unable to detect any similar 

 granules within their texture. On the contrary, on removing part of the surface of 

 the envelopes, the interior, although slightly reddened, exhibited an uniform appear- 

 ance. 



No. 2. Thirty ova were passed into water that had been mixed with seminal fluid, 

 and immediately afterwards a solution of carmine was also added. 



