276 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 
It may be matter of surprise, that, considering the immense quantity of spermatozoa 
which exist even in a microscopic drop of fluid, and considering also the abundant 
which come in contact with the surface of the egg. even when but a small quantity 
of fluid is employed, as in artificial impregnation, a much greater number do not 
penetrate ;than are usually observed to do so. There are conditions and ci.cum- 
stances which affect this result. Thus I have found, in repeated observations, 
only those spermatozoa which, at the moment of first contact with the egg-eme- 
lopes, are in rapid action, and have their body portion directed, either peifectly 
centripetally towards the yelk, or at angles but slightly inclined to it do by any 
possibility enter; while those which happen to be directed horizon ally to 
Lrface of the egg at the instant of contact, always adhere to it latera ly, an o 
their power of motion, but do not penetrate; and the like also is the case 
those which become attached by their caudal end, and even with many w iic 
adhere by their thicker end, when they come into contact with the egg a vei 
acute angles. Further, I have noticed, that a relatively much greater number of 
spermatozoa penetrate the envelopes when supplied to the egg immediately a ei 
this has been removed from the female into water ;-especially when the spermatic 
fluid also has been recently passed from the male;-and more decidedly so when 
!asL fl a male in full season, at which time the movements of the spermatozoa 
Ire most energetic. Thus the chances of penetration through the envelopes, and 
consequently of fecundation of the egg by the spermatozoon, are in diiect lelation 
these circumstances; and inversely to those of an opposite character being less 
proportion to the length of time the egg has been removed from the female oi i 
fluid from the male ; the healthfulness of the parent, and consequent powei of mo lo 
in the spermatozoon;— the temperature of the season, and the quantity supplied o 
Thele were the conclusions deduced from the previous observations, and they have 
been fully borne out by subsequent experiments, some of which have 
the presence of my friends Professors Bell, Bowman, Carpenter, and Mi. Bus , 
Fellows of the Royal Society, and Professor Ellis, who permit me to mention the 
circumstance. . i * uii 
Narcotization of the Spermatozoon.-l may now mention some experiments wine 
were made with the view to test the feciindatory influence of recently obtained spei- 
matozoa when narcotized by chloroform. These experiments were suggested by a 
communication made to me by Mr. Busk, F.R.S., who. after witnessing my mode of 
procuring the eggs of the Frog, conceived that a similar result might be attained by 
narcotizing the gravid animal without killing it, as is necessarily done in my expeii- 
mlf anion putting this opinion to the test he found that it may be accomplished 
with ease and success. It then occurred to bin. to try the effect of 
spermatozoa to the vapour of chloroform, by simply covering the 
contained in a watch-glass covered with blotting-paper wetted with the liq. , 
