THE EXPERIMENTS. 235 



the human femen till the age of 14 or 15; nor 

 do we learn whence they proceed, or how they 

 are yearly renewed in fiflies, &c. Notwith- 

 ftanding all the efibrts of Leeuwenhoek to efta- 

 blifh the generation of fpermatic animals, he 

 leaves the fubjedt in the greateft obfcurity, where 

 it probably would have for ever remained, if 

 we had not dikovered, by the preceding expe- 

 riments, that they are not animals, but organic 

 moving particles, contained originally in the 

 food, and found in vaft numbers in the feminal 

 liquors of animals, which are the mod pure and 

 moft organic extrads derived from the food. 



Leeuwenhoek acknowledges, that he did not 

 always find animalcules in the male femen ; for 

 example, in that of the cock, which he ofcen 

 examined, he never but once faw the eel-like 

 ^animalcules : And, fome years after, he could 

 not difcover thefe eels *, but found animalcules 

 with a large head and a tail, which his drawer 

 eould not perceive. He likewlfe remarks, that, 

 during one feafon, he could not difcover living- 

 animals in the feminal fluid of the cod*!** All 

 thefe difappointments proceeded frOm this cir- 

 cumftancc, that, though he faw moving glo- 

 bules, he was unwilling to acknowledge them to 

 be animals, unlefs they had tails, though it is in 

 the form of globules that they moll generally 

 appear, cither in feminal fluids, or in infufions 



of 



• See torn. 3. p. 370. ^ 



f Tom. 3. p. 306. 



