396 Reviews and Records in Anatomy and Physiology. 
we quote his own language, as used in some of the conclusions 
which he has given. We will commence with the 5th, omitting 
oe 2 a ats four as irrelevant to our point in question: 
at only extremely minute granules of solid matter can 
pee ny vossibility pass into the tissue of the envelopes during en- 
dosmosis ; and that there is no evidence whatever of the existence 
of a fissure or orifice, in the envelopes of the egg of the amphibia, 
at the time of, or before impreguation, capable of admitting the 
spermatozoon to the interior of the yolk-membrane or its contents. 
“6th. That it is the spermatozoon alone which affects impreg- 
nation ; and that this does not take place until the spermatozoon 
is brought into immediate contact with the external layer of the 
ovum. 
“8th. That although direct contact of the spermatozoa with 
the ovum is indispensable to effect impregnation, I have never 
been able to detect any traces of these bodies in contact with the 
yolk-membrane, or even within the substance of the external en- 
velo 
“9th. That impregnation is commenced the instant the sper- 
matozoa are brought into contact with the egg, but a certain 
duration of contact i is essential to its completion. 
“10th. That impregnation is not effected, when the whole or 
the majority of the spermatozoa in contact with the envelopes 
have previously become motionless, and apparently have lost 
vitality, as they are found to have done after the lapse of a longer 
or epee! peri 
11th. That although an exceedingly minute quantity of sper- 
matozoa suffice to impregnate the ovum, the phenomenon of im- 
pregnation takes place more tardily even “witls duration of contact, 
when the number is extremely limited, than when it is in full 
abundance, withoute excess ; while, when the quantity is deficient, 
or the duration of contact too limited, then the phenomenon Is in- 
CoMprers, and partial 1 impregnation only i is effected. 
2th. Partial impregnation is shown in imperfect segmen- 
tation of the yolk ; and is due to the spermatozoa being insuffi- 
cient in quantity, or in duration of contact, or inefficient through 
diminished vitality ; : anid: it may also result from diminished sus- 
ceptibility in the ovum.’ 
Newport’s experiments and observations show, in: brief, that 
contact alone of the spermatic particles with the ovum is requisite 
8 fecundation, that each ovum requires several particles ; an 
at there must be duration of this contact. Here is a limit to 
* In his second series, Newport says he has detected the ¥ ghee particles: within 
the coverings of the egz, and sometimes even partially im in the vitelline 
membrane neath them ;—but he had no evidence that they ace the vitelline cav- 
ity. We consider this fact of penetration within the envelopes as 0 o import in the 
question before us; for, as we hope to be able Se as a ll be regarded 
as contingent and not essential. 
