288 MR. NEWPORT ON THE IMPREGNATION OF THE OVUM IN THE AMPHIBIA 



hundred and six embryos were produced, so that only thirty-three eggs failed; thus 

 leading to the inference that the failure in the experiments (a) and (b) 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 previous. 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 sperma- 

 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 trial, 

 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 unirnpregnated. If the difference in the 

 length of time which elapsed between the encounter of the spermatozoon 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 in each 

 experiment, and that all the conditions were similar. It seems, as it were, inversely, 

 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 foreign 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- 



