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 

 affinities, 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 



* KOLLIKER, SlEBOLD, MlJLLER, WAGNER, &C. 



