t 13 } 



their bodies. That immenfe quan- 

 tity of animal fub fiances, and many- 

 others, which undergo a putrefac- 

 tion by the warmth of the weather, 

 feems to require an additional power 

 or agent to counter-act ic ; and this 

 office is deflined to the leaves. In. 

 frofty weather no animal fubftance 

 is fubject to putrefaction, which, 

 cannot go on without a proper de- 

 gree of heat. The perfpiration of 

 animals is lefs offenfive in the win- 

 ter than in the fummer, and of con- 

 fequence rauft corrupt the atmo- 

 fphere lefs. It feems therefore pro- 

 bable, that, if we are deprived of one 

 way by which air is corrected in the 

 winter, we have alfo at that time lefs 

 caufes which tend to contaminate 

 our element. 



S E C* 



