SEMINAL FILAMENTS. 



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classes of animals, proves that they are essential to the process 

 of impregnation ; but beyond this, and that their contact with 

 the ovum is necessary for its development, nothing is known. 



A, spermatic filaments from the human 

 vas deferens (from Kolliker). 1, magnified 

 850 diameters ; 2, magnified 800 diameters ; 

 a, from the side ; 6, from above. B, sper- 

 matic cells and spermatozoa of the bull 

 undergoing development (from Kolliker) 

 15.0.. i ( spermatic cells, with one or two 

 nuclei, one of them clear; 2, 3, free nuclei, 

 with spermatic filaments forming; 4, the 

 filaments elongated and the body widened ; 

 5, filaments nearly fully developed. C, es- 

 cape of the spermatozoa from their cells in 

 the same animal. 1, spermatic cell contain- 

 ing the spermatozoon coiled up within it; 

 2, the cells elongated by the partial uncoil- 

 ing of the spermatic filament ; 3, a cell from 

 which the filament has in part become free ; 

 4, the same with the body also partially 

 free ; 5, spermatozoon from the epididymis 

 with vestiges of the cell adherent; 6, sper- 

 matozoon from the vas deferens, showing 

 the small enlargement, b, on the filament. 



The seminal fluid is, probably, after the period o puberty, 

 secreted constantly, though, except under excitement, very 

 slowly, in the tubules of the testicles. From these it passes 



