2o6 COMPARISONOF 



In the fame letter to Boerhaave he fays *, that, 

 in the femen of a ram he obferved the animal- 

 cules marching in flocks like fheep ; ' A tribus 

 ' circiter annis teftes arietis, adhuc calentes, ad 

 ' aedes meas deferri curaveram ; cum igitur ma- 

 ' teriam ex epididymibus edud:am, ope micro- 



* fcopii contemplarer, non fine ingente voluptate 



* advertebam animalcula omnia, quotquot inna- 

 ' tabant femini mafculino, eundem natando cur- 



* fum tenere, ita nimirum ut quo itinere priora 



* praenatarent, eodem pofteriora fubfequerenter, 

 ' adeo ut hifce animalculis quafi fit ingenitum, 



* quod oves fad:itare videmus, fcilicet ut praece- 



* dentium veftigiis grex univerfus incedat.' This 

 obfervation, made by Leeilwenhoek in the 1713, 

 and which he regarded as new and fingular, is a 

 fufficient proof that he had never fo attentively 

 examined the feminal fluids of animals as to en- 

 able him to give exad defcriptions of them. In 

 the 1 7 1 3, he ^as 7 1 years of age : He had been 

 in the conftant pra'diice of making experiments 

 with the microfcope for 45 years : He continu- 

 ed to publiih his obfervations during 36 years : 

 And yet, after all this pradice, he now, for the 

 firfl: time, obferved a phaenomenon which is ex- 

 hibited in every femen, and which I have de- 

 fcribed, Exper. IX. in the human femen, Ex- 

 per. Xli. in the femen of a dog, and Exper. 

 XXIX. in the femen of a bitch. To explain the 

 moving of the animalcules of the ram in flocks, 



therefore, 



* Tom. 4. 23. 



