58 A*IIMALCULA OF INFUSIONS. L 



with the animals bearing the greateft analogy 

 and the neareft: to animalcula, I mean infects. 

 Some races do not die at 11° below o, while 

 others perifli at 10°, or at mod at 7°. Many 

 cannot fupport fimple freezing, and others ceafe 

 to live at cold far inferior (i). 



There is this difference between infufion ani-- 

 malcula and infefts expofed to cold ; the former 

 are fufficiently lively to preferve the aQion of their 

 members ; the latter at freezing, and fome before 

 it, lofe all vivacity, and affume the appearance of 

 dead bodies. However, there are a few infeds 

 which, in this refpecl, may be compared to ani- 

 malcula ; befides the podura of Linnaeus, which 

 inhabits the fnows of Sweden (2), I have feen 

 the eels of vinegar retain motion at an intenfe 

 cold. Vinegar does not freeze fo foon as water; 

 fome kinds did not freeze at 16"; others more 

 fpirituous at 7°; and the anguillae always moved 

 while it remained fluid. Eels, hke animalcula, 

 infenfibly become motionlefs on encreafmg the 

 cold ; they fiill move while a thin cruft covers 

 the vinegar ; but the freezing being augmented, 

 motion ceafes, and they are extended in a flraight 

 line, or in one a little curved. If fudden aid is 

 brought, by melting the ice, they will certainly 

 recover ; but if the ice is allowed to harden more, 

 melting will not bring thern to life (3). 



The 



(1) Reaumur, Menioires fur les Infedes, tom. 2.5. 



(2) Fauna Suecica. 



(3) Dr Power obferves, that the eels of vinegar may te 



frozen 



