242 SPECIAL HISTOLOGY. 



unsatisfied sexual excitement, often produce a turgescence of 

 these organs, attended with painful sensations, and most pro- 

 bably with a formation of semen. The subsequent removal of this 

 fulness does not, however, appear to me incontestably to prove 

 any absorption, because a difference in the quantity of blood 

 in the testis, and the passing of the semen into the v. deferentia 

 are sufficient to account for the restoration of the usual condi- 

 tion. The fluid constituting a seminal emission is not pure 

 semen, but in great part the secretion of the vesiculae seminales 

 and prostate, and affords no criterion by which to estimate the 

 energy of the secretion of the testes. The formation of the 

 semen itself certainly does not proceed rapidly and copiously, 

 as might be concluded from the relatively small quantity of 

 blood contained in the testes, and from its slow motion in them, 

 necessarily consequent upon the anatomical conditions; and 

 as is also evident from the fact, that after a few previous emis- 

 sions, even in the most vigorous organisms, a certain time is 

 requisite for the preparation of a fresh secretion. The secre- 

 tions of the accessory glands are perhaps simply intended for 

 the dilution of the semen. 



That the seminal filaments are not animalcules, but elemen- 

 tary parts of the male organism, it is useless at the present 

 time to attempt to demonstrate ; although it is still as much 

 as ever unknown, and will not easily soon be ascertained, what 

 is effected by their curious movements, which are obviously 

 intended to convey them to the ovum, from the uterus, which 

 they probably reach in fruitful congress. Nor, from the expe- 

 riments of Prevost, Dumas, Schwann, and Leuckart, and the 

 later researches of Newport (Phil. Trans. 1851, 1,) can the 

 least doubt be entertained that they are the true impregnating 

 agent, and for the purpose of impregnation must necessarily 

 come in contact with the ovum. The circumstance that motile 

 spermatic filaments alone possess the fertilising property, and, 

 according to Newport, that the effect upon the ovum takes 

 place immediately upon the contact, although a short duration 

 of the contact of the spermatic filament with the ovum is 

 necessary to render it efficient, also shows, as it appears to me, 

 that they do not act by affording any material substance to 

 the egg, but in consequence of their exciting actions in it, as 

 bodies in a state of peculiar activity. In my first work upon 



