288 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 
hundred and six embryos were produced, so that orAy thirty^three eggs failed; thus 
leading to the inference that the failure in the experiments (n) and (6) was owing 
to the spermatozoa being destroyed; and, consequently, that the application of the 
substance of the body of the spermatozoon to the egg is not alone sufficient to effect 
fecundation ; so that fecundation cannot be regarded as the result of simple chemical 
combination of the substance of the spermatozoon with that of the egg, but, essentially, 
may be due to some dynamical influence in that body. 
At the time of making these experiments I made also two others with a view to this 
hypothesis; and for the sake of correct comparison employed eggs from the same 
female and placed them in a precisely similar condition with regard to light, heat, 
and the quantity of water employed. The fecundatory fluid, however, was not from 
a male in full season, as above, but was what may properly be regarded as senile, 
it being purposely obtained from some frogs which had been kept separate from the 
females, having already paired and spawned from five to ten days pre%nous. It was 
slightly translucent, and contained, relatively, but few living spermatozoa, the 
majority of which were languid in their movements ; but there were many which 
appeared perfectly dead and motionless, and there was a good proportion of spernm- 
tozoal cells. In the first experiment one hundred and sixty-seven eggs were supplied 
with a portion of this fluid, and segmentation commenced in some of them in four 
hours and forty-two minutes, or not so soon as in the experiment (c) by twenty-eight 
minutes, and afterwards only forty -three embryos were produced. In the second triid, 
made at the same time with one hundred and seventy-three eggs, segmentation took 
place in four hours and forty-one minutes, and one hundred and twenty-six embryos 
were produced, forty-seven eggs being unimpregnated. If the difference in the 
length of time which elapsed between the encounter of the spm-matozoon with the 
egg and the commencement of segmentation in these two experiments, as compared 
with the preceding one, be not fairly referable to a less degree of vitalizing power in 
the spermatozoon in the latter, it seems difficult to understand to what other cause 
it can be assigned ; seeing that the eggs employed were from the same female m eaci 
experiment, and that all the conditions were similar. It seems, as it were, inverse y, 
to show, that the most important condition of the impregnating agent is its possession 
of some dynamical quality, the degree or intensity of which is expressed in that of 
its power of motion, and which, possibly, it may transmit from itself to the egg, during 
the act of fecundation. 
These results sufficiently mark the injurious effect produced on the fecundatory 
fluid by trituration, whether with or without admixture of foreipi substances ; and 
while these seem to prove that attrition of the spermatic bodies with particles of solid 
matter, by lacerating and mechanically destroying them, is fatal to their function, 
other experiments showed that even their simple admixture with any finely com- 
minuted solid materials greatly interferes with their operation, by the mechanical 
impediment which such materials oppose to their free motion, and to their penetra- 
