214 
MR. NEWPORT ON TflE IMPREGNATION OF 
with water before ova were passed into it. At Jive minutes after immersion of these 
ova, I have found large quantities of spermatozoa already adhering to the surface of 
their then expanding envelopes. But many of them have already been coiled on them- 
selves, and were perfectly motionless. The water still contained very many dissemi- 
nated through every part of it, but most of them, with few exceptions, have appeared 
to be rigid, and to have become enlarged in diameter, but not increased in length. 
This change has appeared to be due to the hygroscopic nature of these bodies, as 
formerly pointed out by Siebold*. Possibly this nature may have some reference to 
impregnation. Repeated observations lead me to believe that, in whatever way the 
spermatozoa are concerned in impregnation, they do not penetrate bodily into the 
ovum, but merely adhere to the surface. 
Prevost and Dumas concluded'!' from their investigations, that the spermatozoa of 
the Triton and Frog do penetrate into the envelope of the egg; and they state that 
they had fecundated ova taken from the ducts of the Triton, and after the lapse of 
three hours, having first carefully washed them to remove all that were merely 
adhering to the surface, have made sections of the envelopes of the egg, and, with the 
aid of the microscope, have found living spermatozoa still struggling within. Their 
words are — “ Une grande quantity d’animalcules encore mouvans, et qui semblaient 
se debattre dans cette esp^ce de gelee oh ils se trouvaient emprisonnes. On en voyait 
partout meme au contact des membranes de Foeuf.” Further, that they had repeated 
this experiment on the ova of the Frog, and found the envelope penetrated in like 
manner with spermatozoa, still moving, but not changing place. I regret much that 
my investigations do not enable me to confirm these observations, which seem to me 
to be due to the circumstance of these physiologists having regarded the objects on the 
surface as being in the interior. I have many times sought for spermatozoa within 
the substance of the egg-envelope of the Frog, at different periods between that of 
first contact with impregnating fluid and the time when cleavage of the yelk has com- 
menced, and have constantly found them on the surface, but have never, even in a 
single instance, observed any appearance of them in the substance of the envelope, 
nor anything which induced me to suspect that they penetrate bodily into it. They 
have been present on the surface, and adherent to it, even from within a few seconds 
after contact, to so late as the sixth hour, but have usually been motionless ; and most 
of them have had the caudal portion folded back on the body. I was led to make 
these observations on the egg of the Frog, — before I was aware of MM. Prevost and 
Dumas’ views, — from the circumstance of Dr. Martin Barry having mentioned:|; that 
an orifice or fissure exists in the thick investing membrane of the ovum of the Rabbit, 
through which, at the time of impregnation, he believed the spermatozoon to enter. 
All the observations I have been able to make on the ovum of the Frog, both micro- 
scopically and experimentally, are opposed to the belief in the existence of any perfo- 
* Muller’s Archiv, 1836. t Loc. cit., vol. ii. p. 133. 
J Philosophical Transactions, 1840, p. 535. 
