AND ON THE DIRECT AGENCY OF THE SPERMATOZOON. 
265 
completed, and an embryo became developed. But if, instead of the spermatozoa 
being thus supplied in a minimum quantity from the point of a pin, they were sup- 
plied in greater quantity from the head, then impregnation was almost always effected ; 
and this result was rendered the more certain by allowing the head to be drained of 
the adhering bodies for a moment or two, as from the point, by which a much larger 
quantity of the impregnating agents was deposited. In these instances it was rare 
that impregnation was not effected. These results appear to show, that, whatever may 
be the precise quantity necessary to effect healthful impregnation, it has some definite 
relation to the effect to be produced in the contents of the ovum — that a definite 
quantity of spermatozoa, or spermatic influence is required to fecundate, and that 
the perfection of fecundation has relation to the degree of impregnating influence. 
They seem to show, also, that fecundation is not the simple result of the pene- 
tration into the egg of a single isolated spermatozoon, but probably of some definite 
number of these bodies, or of a definite amount of influence supplied, through their 
encounter. We are thus led to perceive that the same law of relation between 
cause and effect, — between a definite amount of influence expended, and definite 
results, — which has long constituted the basis of our knowledge respecting chemical 
aflSnities, and which is now being demonstrated, as that also of the other forces of 
inorganic nature, may equally pervade and control these material combinations 
among the organic affinities. Further, the observations, now mentioned, seem to 
put to rest the last remaining question respecting the independent animality of the 
spermatic bodies, and to show that these, like the cilia, are mere elementary parts 
of the adult male organization, — as many physiologists believe*, — as the contents of 
the ova are of that of the female. 
All my experiments on the egg of the Amphibia serve to show, that even with a 
definite quantity or number of spermatozoa, no impregnation is effected, if, before 
the spermatozoa are brought into contact with the egg, they have all ceased to exhibit 
that motion which constitutes their marked characteristic. Thus then, it seems that, 
independent of the important question as to whether these bodies yield any material 
substance for combination with the constituents of the egg, through the usual chemical 
affinities of matter, — the quantity of influence to be supplied to produce the healthful 
result is definite, and that, whatever be its nature or essence, it is always charac- 
terized by a definite degree of motion in the spermatozoon. Further, all the observa- 
tions I have made on the spermatozoa tend to show that their motion is rendered 
more vivid and intense by an increase of heat, but that, in proportion to such increase, 
it is so much the sooner exhausted ; as, on the other hand, it has long been known 
that it is diminished by reduction of temperature, but increased in duration. Many 
of the observations lead to the view, that the power, in a given quantity or number 
of the spermatozoa, to effect impregnation, is more in proportion to the amount, 
quantity, or intensity of the motion exhibited by these bodies than to their actual 
* Kollikee, Siebold, Mullee, Wagnee, &c. 
