394 Reviews and Records in Anatomy and Physiology. 
who, in this department have written upon what they really 
knew nothing, yet speculated much, we shall attempt to show the 
state of our real knowledge on this ultimatissimum of physiology 
—the modus operandi of fecundation. 
Modern histological studies, have we think, pretty definitely 
settled two fundamental and important points: Ist. That the 
ovum is, morphologically, only a nucleolated cell; and 2nd. That 
the sperm-cell is the true homologue of the ovum. 
The ovum (fecundated) produces the embryo; the sperm-cell 
the spermatic particle. The embryo and the spermatic particle 
are the correlative representatives of the female and the male sex. 
One is the metamorphosed nucleus (vitellus) of the one; the 
other the metamorphosed nucleus (nucleus of the daughter-cell) 
- of the other. In both, the ovum and sperm-cell, the process of 
segmentation seems a necessary preliminary to the evolution of 
the new being.* 
The strict correlation between the essential products of the 
sexes is as wonderful as it is beautifully suggestive of the unity 
and simplicity of plan by which nature proceeds. This point, 
so seductive in all its relations, might be dwelt upon in detail, 
but we will continue with main and general facts. The ovum, asa 
nucleated or nucleolated cell, continues to grow, and whatever size 
it may attain to by the endogenous formation within its capsule of 
new cells, yet, when complete, it is, (even though belonging to the 
Ostrich or Epiornis, ) morphologically, only a great compound nu- 
cleated or nucleolated cell. All these conditions of origin, growth 
and maturity, can be satisfactorily studied in the lower animals, 
and we would especially recommend the compound Ascidie for 
this purpose. The ovum, thus complete, is ready for fecundation. 
We have already said that the sperm-cell is the analogue, or 
more properly homologue, of the ovum; its origin and evelop- 
ment, as we have traced them in all their details, are precisely the 
same as those of the ovum. The sperm-cell increases to a defi- 
nite size, its nucleus (vitellus) then regularly segments 2, 4, 8, 16, 
é&c., and the results of this segmentation, are daughter-cells. The 
condition of the sperm-cell at this moment is like that of the ovum 
produced by the same process of segmentation. I mean the mul 
berry-like condition. But at this point there is a digression, for 
with the sperm-cell the nucleus of each of the daughter-cells 18 
changed into a spermatic particle, while with the ovum, the 
whole mass is metamorphosed into the new being by a process 
of substitution. 
he spermatic particle, then, is only a metamorphosed nucleus 
of acell, and, perhaps, were the analogy carried out completely, 
each daughter-cell would be the representative of a miniature 
ovum. 
*See Researches on the origi of the spermatic 
ae among the Saphire Voce ton deen dpel. 2 84% 
