t§6 ANIMALCULA OF INFUSIONS. I. 



The firjfl extradl confirms what M. de Sauf- 

 fure and myfelf remarked of the erroneous idea 

 which had induced the belief of the fmaller in- 

 fufion animalcula being generated by others larg- 

 er, and thefe by fome of ftill a larger fize, ac- 

 cording to M. Needham and de BufFon's fenti- 

 ments, who have undoubtedly been mifled by a 

 faft very fedu£live in appearance. It often hap- 

 pens that the whole animalcula of an infufion 

 are of the largeft fize. By an invariable law, the 

 life of animalcula has a determinate period j 

 therefore the largeft perifli in a certain time. 

 Frequently, when they begin to diminifh, a fmall- 

 er fpecies is generated, and thefe are fucceeded 

 by fome ftill fmaller ; laft of all comes a colony 

 of lefs fize than any of the whole. One accuf- 

 tomed to explore nature, and to have nothing but 

 her operations in view, will foon perceive there 

 is no relation of parent and offspring among the 

 fucceflive generations. But whoever difdains 

 the trouble of analyfing natural phenomena to 

 the utmoft, and fancies an hypothefis, that the 

 fmaller races proceed from the larger, will readi- 

 ly difcover it in every fuccefTive colony of a dif- 

 ferent fize. 



If, from the reafons adduced, we are conftrained 

 to confider infufion animalcula real animals, what 

 can we anfwer to M. Needham, who conceives 

 himfelf obliged to fuppofe them machines fimply 



vital. 



