AND ON THE DIRECT AGENCY OF THE SPERMATOZOON. 257 



A second comparative trial was made on the 15th of March. Three eggs in sepa- 

 rate cells were each touched once with the fine pin-point loaded with fluid which 

 had been obtained only twenty minutes before. The temperature at the time of the 

 experiment was 56 FAHR., but the eggs were removed within a few minutes after- 

 wards to a higher temperature, which was gradually increased to 64-5 FAHR. Seg- 

 mentation took place in one of these eggs in three hours and thirty -nine minutes, and 

 this egg afterwards produced an embryo. But the remaining 'two were not impreg- 

 nated. Three other eggs in separate cells, were, at the same time as the preceding, 

 each once touched with the loaded pin-head, and two out of the three underwent 

 segmentation at the end of three hours and thirty-three minutes. In a further 

 experiment, made at the same time, sixteen eggs included in one cell were touched 

 with the loaded pin's-head when the fluid had been obtained about half an hour 

 before. Four of these eggs underwent segmentation in three hours and Jifty '-three 

 minutes, and afterwards produced embryos, the remaining eggs being unproductive. 

 Another experiment was made with nineteen eggs in a single cell, by pin-head 

 application of the fluid, and eleven of these were fecundated and began to be seg- 

 mented in three hours and forty-two minutes, and ultimately produced embryos, the 

 remaining eight being sterile. Some of these failures were probably due to the cir- 

 cumstance that the fecundatory fluid was not applied to the most susceptible part of 

 the egg, yet the general results sufficiently show not only that fecundation is more 

 surely and quickly effected at a moderately high than at a low temperature, but also 

 that it is so, more or less certainly and quickly, in proportion to the amount of 

 influence supplied. 



These facts lead us to some further consideration of the results of the application 

 of definite quantities of the fecundatory agent to the egg, as affecting the develop- 

 ment of the embryo, and possibly also as influencing both the evolution of its physical 

 structure and psychical condition. I have little hesitation in believing that whatever 

 be the precise nature of the influence communicated by the fecundatory agent to the 

 egg, that it is only after full and complete impregnation that perfectly normal and 

 healthy embryos are formed, and ultimately attain to the maturity of the species. 

 And yet we have already seen that when there is great excess of the agent, either 

 that no embryo is produced, or that its development is not completed. 



A few days after making the last-mentioned experiments I repeated them with 

 another object in view, and then obtained a result which had occurred on previous 

 occasions, but being less distinctly marked had been almost overlooked. 



About twenty eggs had been placed in separate cells, and fecundation attempted 

 by pin-head application of fluid which had been obtained from a partially exhausted 

 and debilitated male, at the end of the season, and which had been employed from 

 want of a more healthy individual. The fluid, when examined by the microscope, was 

 found to contain very many perfectly motionless spermatozoa, besides a large quantity 

 of cells. The inefficiency of this male was inferred from the circumstance that the 



