AND ON THE DIRECT AGENCY OF THE SPERMATOZOON. 281 
are detailed in that paper; viz. that when diluted spermatic fluid, recently obtained, 
is applied to a set of eggs, and— as soon afterwards as the experiment can be made, 
a solution of potass, of such a strength as is known by previous microscopic observa- 
tion to have the property of instantly decomposing the spermatic body,— the solution 
being washed away quickly after its application, by repeated quantities of water,— 
to prevent its affecting the egg itself— that then— in some instances — even when the 
interval of time between the application of the spermatic fluid and the subsequent ap- 
plication of the potass does not exceed a few seconds, — impregnation of the egg is 
effected; as is proved by the formation of the chamber, the segmentation of the 
yelk, and perhaps the formation of an embryo. Further, that, all circumstances 
being similar, excepting only that the interval of time between the application of the 
spermatic fluid, and, subsequently, that of the solution of potass be prolonged, — the 
production of an embryo is not only more certain to take place, but the number of 
embryos produced is increased. The now ascertained fact of almost instantaneous 
penetration by the spermatozoon, which, as before shown, sometimes arrives at the 
vitelline membrane in less than one minute after its application to the egg, confirms 
the principal conclusion deduced from the potass experiments at the time they were 
made, viz. that impregnation is commenced at the instant the spermatozoon is in con- 
tact with the egg ; while it also seems to afford the true explanation of the nature of 
those experiments, in which it may now be presumed that some spermatozoa had 
actually penetrated into the substance of the envelopes before the application of the 
solution of potass, and thus had already passed out of the reach of its destructive 
influence, the effect of which on the egg itself was obviated by speedy dilution and 
ablution with water. 
The potass experiments may thus be regarded as confirming by anticipation the 
results now obtained by direct observation with the microscope, with respect to the 
rapidity of operation by the spermatozoon ; and they seem also to support the view 
of the essentiality of the motor power of this body to its functional action. A similar 
view may be taken, as indeed was held at the time, of the nature of the Carmine, the 
Gum, and the Starch experiments, that the operation of these substances in preventing 
the fecundation of the egg is entirely mechanical, and that they do so simply by offering 
a meehanical impediment to the spermatozoon, a conclusion which seems to be fully 
supported in the present inquiry. 
14. NATURE OF THE INFLUENCE OF THE SPERMATOZOON. 
Having seen in the preceding experiments and observations that fecundation of 
the egg is effected by the spermatozoon only while this body retains and continues to 
give evidence of its vitality in its power of motion, and that its vitality either may be 
destroyed, or its operation be for a time entirely arrested by electricity and by chlo- 
rofoim, the question naturally arises — in what way, then, is its fecundatory influence 
to be explained ? Is it simply by difliuence of the substance of the spermatozoon, and 
the chemical fusion or combination of this with the contents of the egg, after the sper- 
