1. ANIMALCULA OF INFUSIONS, IJj 



ference of cold required to occafion torpor, 

 mufl arife from the different nature of the muf- 

 cular fibre, which in fome animals is more fuf- 

 ceptible of it than in others. If the power of cold 

 is encreafed, torpor degenerates into death. 



The reafon affigned by phyfiologifts for the 

 death of man and animals from cold, is certainly 

 very plaufible. The contraftion of the cutane- 

 ous veifels forces a reflux of the blood to the in- 

 ternal parts of the body ; whence is occafioned 

 the infenfibility and ftiffnefs of our fingers and 

 the extreme palenefs of the body. Cold be- 

 coming more intenfe, the internal and large vef- 

 fels contract, and the reflux of blood is greater ; 

 but thofe of the brain, being better defended by 

 the cranium from the injuries of the air, are not 

 fo liable to contraft. Blood flows copioufly in 



the 



}y fell to 32° ; and a cruft of ice, a quarter of an inch 

 thick, formed on the top. Still the animals could move, 

 though languidly, and a very faint motion was percep- 

 tible in the legs of one. Thus the water remained fome 

 hours. In twenty hours after the experiment began, the 

 thermometer flood at 36''. None of the hydrachnae 

 weie torpid. 



Experiments were at the fame time made on feveral 

 Other aquatic animals. Squillae and gyrini did not be- 

 come torpid at 32*. Perhaps thisfubje^fl deferves further 

 coiifideration. — T, 



