ON GENERATION. 159 



almoR' entirely fimilar to thofe in the human fe- 

 men, [pi. V. fig. 13.]. Their tails and their 

 form were almoll prccifely the fame with thofe 

 reprefented in pi. IV. fig. 7. where the liquor had 

 been liquified for two or three hours. I in vain 

 fearched this liquor for the filaments which ap- 

 peared in that of men. I only remarked fome long 

 and very delicate threads, exadly fimilar to thofe 

 which ferved for tails to the globules. Thefe 

 threads contained no globules ; neither had they 

 any motion. The globules with tails feemed to 

 move with more vivacity than thofe in the hu- 

 man femen. They had hardly any horizontal 

 vibrations ; but they always rolled vertically. 

 Their number was not great ; and, though their 

 progreflive motion was quicker, they took up 

 fome time in paffing over the field of the micro- 

 fcope. I examined this liquor during three 

 hours, and could obferve no change. I conti- 

 nued my examination, from time to time, for 

 ieveral days, and remarked, that the number of 

 movmg bodies gradually diminiilied. On the 

 fecond day, the greateft part of them had loft 

 their tails : On the third, very few of them re- 

 tained their tails ; on the fourth, however, fome 

 tails ftill adhered. The liquor had now de- 

 pofited a whitilh fediment, which appeared to 

 be compofed of globules without motion, and 

 fome Imall threads that feemed to be the tails 

 which had feparated from the globules. Some 

 globules appeared to have dead ones attached to 



them ; 



