114 ANIMALCULA OF INFUSIONS. I. 



milar to thefe ; their animalcula died in about 

 two days (i). 



The nature of certain animals is wonderful. 

 They continue their ordinary corporal fundions 

 in vacuo a confiderable time. Vipers and fnakes 

 will creep, and leeches fwim in fluids. Some 

 infe6ls feed, and others perform, the work of ge- 

 neration (2) : Such is the nature of animalcula. 

 In a vacuum, they preferve their wonted mo- 

 tions, afcending or fniking, darting to the furface 

 of the infufion, and diAang into its deeps, or driv- 

 ing before them the floating particles on which 

 they feed. I fliall afterwards fpeak of their fmgu- 

 lar modes of propagation ; and this alfo fucceeds 

 for feveral days in vacuo. In procefs of time, 

 and according to the flrength of the animalcula, 

 motion relaxes and ends in death. It fometimes 

 liappens, but rarely, that, being taken from the 

 receiver, and left expofed to the open air, they 

 revive. 



Thefe experiments have confirmed two obfer- 

 vations in my Differtation ; the ufual fterility of 

 infufions in vacuo ; and their fertility when the 

 air was only rarified. No animal or vegetable 

 fubftance macerated in vacuo ever produced a 

 fmgle animalcule : the reverfe uniformly happen- 

 ed, on leaving a portion of air in the receiver. 

 As much as keeps thirteen inches of mercury in 



equilibrio 



(i) ^apitolo, 10, (2) Sperienze del Cimento. 



