naturalists are now inclined to admit the general truth of the theory of
evolution, but they differ widely respecting the mode in which it
occurred.


THE PROCESS OF GENERATION.


The vital _principle_, represented in the _sperm_-cell by a
spermatozoön, must be imparted to a _germ_-cell in order to effect
impregnation. After touching each other, separate them immediately, and
observe the result. If, with the aid of a powerful lens, we directly
examine the spermatozoön, it will be perceived that, for a short time,
it preserves its dimensions and retains all its material aspects. But it
does not long withstand the siege of decay, and, having fulfilled its
destiny, loses its organic characteristics, and begins to shrink.

If we examine the fertilized germ, we discover unusual activity, the
result of impregnation. Organic processes succeed one another with
wonderful regularity, as if wrought out by inexplicable intelligence.
Here begin the functions which constitute human physiology.

Generation requires that a spermatozoön be brought into actual contact
with a germ that fecundation may follow. If a spermatic cell, or
spermatozoön, together with several unimpregnated ova, no matter how
near to one another, if not actually touching, be placed on the concave
surface of a watch-crystal, and covered with another crystal, keeping
them warm, and even though the vapor of the ova envelops it, no
impregnation will occur. Place the spermatozoön in contact with an ovum,
and impregnation is instantly and perfectly accomplished. Should this