EXPERIMENTS. 2ii 



femen of the dog. Inftead of diftind filaments, 

 it is generally compofed of a compaft mucilage, 

 in which we With difficulty perceive Tome fiila- 

 mentous parts ; and yet this mucilage gives 

 birth to moving bodies fimilar to thofe in the 

 human femen. 



The motion of thefe bodies continues longer 

 in the fluid of the dog, than in that of man^ 

 which enables us more eafily to diftinguifh the 

 change of form above remarked. The moment 

 the fluid ifl'ues from the body of the animal, we 

 find moft of the animalcules pofl^ciTed of tails. 

 In 12, 24, or 36 hours afterwards, almoft the 

 whole tails difappear; we then perceive only 

 oval bodies moving about, and generally with 

 more rapidity than at firft. 



The moving bodies are always below the fur- 

 face of the liquor. Several large tranfparent 

 air-bubbles commonly appear on the furface i 

 but they have no motion, urilefs when the li- 

 quor is agitated. Below the moving bodies we 

 often perceive others ftill more minute : Thefe 

 have no tails; but moft of them mOve : And, irt 

 general, I have remarked, that, of the number- 

 lefs globules in all thefe liquors, the fmalleft are 

 generally blacker and more obfcure than the o- 

 thers; and that thofe which are extremely mi- 

 nute and tranfparent have little or no motion. 

 They feem likewife to have more fpecific gravi- 

 ty ; for they are always funk deene'l in the 

 fluid. 



O a C ii A A'a 



