578 
DR. NELSON ON THE REPRODUCTION OP THE ASCARIS MYSTAX. 
that of its centre ; hence the particles already mentioned could only have existed in 
the substance of the ovule. 
Another objection might be raised ; admitting the particles to have been situated 
in the substance of the ovule, might they not have been oil-globules, like those seen 
in the unfecundated egg ? 
The reply to this is most satisfactory ; for not only were the particles elongated 
and cylindrical (figs. 59,60 //), but the one extremity was closed, and the other open ; 
hence they could only have been the spermatic particles of the male. 
I cannot enter here upon the consideration of the changes which occur in the 
mammiferous ovum, but confine myself to a few remarks. 
Dr. Martin Barry says, “ On one occasion, in an ovum of 5^ hours, I saw in the 
orifice of the membrane” (the external membrane of the ovum) “an object very 
much resembling a spermatozoon which had increased in size ... I am not prepared 
to say that this was certainly a spermatozoon, but it seems proper to record the 
observation.” 
Now, whether we believe Dr. Barry to have really seen the penetration of the 
spermatozoon into the mammiferous ovum, or whether we agree with Bischoff and 
most other distinguished authors, and deny the correctness of Dr. Barry’s observa- 
tion, as well as the possibility of any such occurrence, the present investigations 
appear to be the first in which the fact of the penetration of spermatozoa into the 
ovum has been distinctly seen and clearly established, in one of the most highly 
organized of the entozoa. 
The accuracy of these observations is satisfactorily borne out, and will be more 
readily admitted, as we continue to trace the progress of the ovule, the changes of 
the spermatic particles, and the development of the ovum. 
The accompanying drawings present these appearances as exactly as possible, 
being taken originally from actual specimens, by means of a camera lucida. In 
some we find the broken margin of small extent (figs. 58, 60 c ) ; in others it embraces 
nearly one half of the circumference (fig. 59 c). Some give a faint indication of the 
contained germinal vesicle (fig. 60 b) ; but in most the granules are too opake to 
admit of its being seen at all (figs. 58, 59). Let us now pass to the examination of 
the changes which take plaee in the ovule subsequent to the penetration of the 
spermatic particles. 
The ovule, it must be remembered, is still in the oviduct; the secretive portion of 
the system, and that in which the false ova receive an enveloping membrane 
(figs. 54 to 57 y*). Almost immediately therefore that the ovule has entered the 
oviduct, traces of a chorion, as a very delicate membrane, begin to appear (fig. 61/*), 
covering at first those portions only of the surface that remain smooth and entire 
(figs. 61, 62/*) ; but as we descend, enclosing by degrees the ruptures themselves, 
and surrounding thus the whole ovule in one continuous envelope (fig. 63 /), with 
