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VIII. Researches on the Impregnation of the Ovum in the Amphibia ; and on the Early 
Stages of Development of the Embryo. ( Third Series.) By the late George 
Newport, F.R.S., F.L.S. 8$c. Selected and arranged from the Authors MSS.*, 
by George Viner Ellis, Professor of Anatomy in University College, London. 
Communicated by Sir John Forbes, M.D., F.R.S. 
Received June 6th, — Read June 15th, 1854. 
In a note dated April 18th, 1853, which was added to my last paper on the 
“Impregnation of the Ovum -f-,” whilst it was printing, I recorded the fact that, 
“ through the adoption of a different mode of examination” from that which I had 
previously employed, I had seen the spermatozoon pass through the gelatinous 
covering and the vitelline membrane of the egg into the vitelline chamber and the 
yelk. This fact of the penetration of the spermatozoon into the yelk is of such im- 
portance as to make it necessary for me to state, with precision, all the circumstances 
connected with it, and to detail the exact course I have pursued. These particulars 
were not given when I announced the fact, because they would have exceeded the 
limits of a supplementary note ; but as the omission of them has exposed my state- 
ment to considerable doubt on the part of one of the most distinguished and truthful 
of physiologists (Professor Bischoff^), it is the more necessary that I now detail pre- 
cisely my mode of proceeding^. I think it will then appear, that the difficulties which 
have hitherto prevented a solution of the question of the penetration of the egg of the 
Frog by the spermatozoon are in chief part, if not entirely overcome, and that this 
egg, far from being the least fitted, is perhaps one of those best adapted for arriving 
[* A great part of this paper was written by Mr. Newport, with the intention of presenting it to this Society ; 
and the rest has been compiled from his Note Books. None of the observations were made later than the Spring 
of 1853.— G.V.E.] 
f Philosophical Transactions for 1853, p. 271. 
J In a paper purporting to refute the opinions of Dr. Keber and Dr. Nelson concerning the penetration of 
the spermatozoon into the ovum, “ Widerlegung, &c. &c., von Dr. Th. L. W. Bischoff, mit einem Zusatz 
von Dr. Rud. Leuckart.” 
[§ Since the above sentence was written Professor Bischoff has investigated, this spring (1854), the im- 
pregnation of the egg of the Frog, and has confirmed the statement of Mr. Newport respecting the penetration 
of the spermatozoon. See his pamphlet headed “Bestatigung des von Dr. Newport bei den Batrachien und 
Dr. Barry bei den Kaninchen behaupteten Eindringens der Spermatozoiden in das Ei.” In this publication 
he asserts that Mr. Newport is the discoverer of the phenomenon of the penetration of the spermatozoon into 
the egg by its own movement. — G.V.E.] 
