204 ANIMALCULA OF INFUSIONS. L 



VI. I now come to that article of your letter 

 which has given me the mod agreeable furprifej 

 and affords mofl ample matter for refledion. 

 You have completely proved that the fmallefl 

 animalcula, or thofe I denominate the loweji dafs, 

 originate and expand in infufions expofed froip. 

 half a minute to twelve minutes to the effefts 

 of boiling water, in veffels hermetically fealed ; 

 while it is at the fame time demonftrated that the 

 animalcula themfelves periftied at io6 and io8^. 



Here undoubtedly is a moft important fadt 

 which philofophers would never have fufpeded 

 without deep meditation on the nature of germs, 

 and their analogy with the elements. This ex- 

 cellent difcovery has given me much pleafurc : it 

 feems to corroborate my fentiments concerning 

 germs ; and the reflexions which it has excited 

 fliall be fubmitted to your opinion. 



You know, my dear friend, that the more dia- 

 phanous a body is, the lefs is it heated by the 

 rays of the fun ; and the greater the number of 

 pores, the more open and dired, the lefs do the 

 rays aft on their fides. The celebrated Bouguer 

 reafonably attributes the exceflive cold felt on the 

 highefl: mountains to the extreme rarity of the 

 air admitting too free palfage to the folar rays 

 for them to make any fenfible imprelTion on this 

 fluid. It is eafy to conceive that fome bodies may 

 pxift, fo thin;, homogeijeous, and perfe^Iy diapha- 

 nous. 



