586 
DR. NELSON ON THE REPRODUCTION OF THE ASCARIS MYSTAX. 
ovary, being part of the female, shares her life, the vitality possessed by the germinal 
particle can only be derived from that of the mother.* 
From this, it appears that the embryo or young Ascaris mystax obtains its vitality 
solely from the mother, but that certain conditions are necessary for the continuance, 
maintenance and development of that life ; and that these conditions are alone 
furnished by the changes effected by the product of the male, on the matters imme- 
diately surrounding the living cell. 
When the male secretion is not present, when the above conditions are not ful- 
filled, life ceases ; the vital point dies ; and although the surrounding substance does 
not immediately perish, yet it no longer encloses a germinal vesicle, or even a 
germinal spot. 
Finally, I would desire to draw attention to the beautiful analogy that exists 
between the products of the ovarian and testicular tubes. The csecal extremities, 
of both the male and female reproductive systems, throw off solid particles of the 
same size, shape and appearance ; both kinds soon present spots in their centres, 
and both swell up into nucleated cells. Yet the one is a seminal, and the other a 
germinal vesicle. 
Granules are now accumulated round both. Both might be called ovules with 
equal propriety; so analogous are they in structure, that size alone distinguishes 
them. But the one is an ovule, and the other a granular mass. 
The granular matter of the ovule dissolves, the germinal vesicle enlarges and dis- 
appears, setting free its nucleus. 
The seminal mass likewise loses its granular covering; the seminal vesicle en- 
larges, and by disappearing, its nucleus is also set free. 
Thus far the analogy is complete, but here it ends; the transformed nucleus of 
the male cell enters the granular vitelline substance of the female ovule, perishing 
by solution ; while the nucleus of the germinal vesicle enlarges, divides, subdivides 
and redivides, till a mass of granules are formed, each possessed of an individual 
existence, and together capable of producing a living whole ; a worm in every 
respect like its parent, endowed, like it, with the powers of assimilation, locomotion, 
and reproduction. 
A new life therefore is not generated during the development of a new being, by 
the happy combination of physical forces ; but the same life bestowed by God at the 
creation, continues without intermission, transmitted from niother to offspring, per- 
vading and redeveloping itself in each individual member of the species. 
