TNTRODUCTdRY OBSERVATIONS. XS 



and ingenuity of philofophers have been equally 

 exercifed. Their infinite multitudes, their varie- 

 ties, the places of abode, and above every thing, 

 their extreme minutenefs, have all confpired to 

 retard our inquiries into their real nature. Let 

 one conceive himfelf, in a moment, conveyed ta 

 a region where the properties, the figure, and 

 motion of every animal are unknown, and he 

 will be able to form fome idea of what infufion 

 animalcula are. The amazing variety of figure be- 

 held at once, and their motions, will firfl attradl: 

 his attention. One is a long flender line, another is 

 an eel or a ferpent. Some are circular, elliptical, 

 and globular, others cylindrical or triangular. 

 One is a thin flat plate, another like a number 

 of articulated reeds. Several have a long tail, al- 

 moft invifible, or the pofterior part is terminated 

 by two ftrong horns. One is like a funnel, an- 

 other like a bell, and many cannot be referred to 

 any object familiar to our fenfes. Certain animal- 

 cula can change their figure at pleafure. Some- 

 times they are extended to immoderate length, 

 then contraded almoft into nothing j fometimes 

 curved like a leech, ftretched or coiled like a 

 fnake. At one moment an animalcule is inflat- 

 ed, and the next it is flaccid. Some are perfed- 

 ly opaque ; fome fcarcely vifible, from extreme 

 tranfparency. Numbers have no apparent or- 

 gans ; and many are covered with tubercles or 



briftles* 



