Sect. V. Agriculture and Vegetation. 79 



IF vegetables are examined chymically 

 after putrefaction, they afford principles 

 very different from what they did before it. 

 Their falts, which were before fixed, are 

 now become volatile, and their oils are 

 much more volatile and foetid than what 

 they were. The foetid fmell of putrefied 

 bodies is owing to thefe volatile foetid oils 

 flying continually off. This greater vola- 

 tility in the falts and oils arifes from their 

 being more attenuated than what they 

 were. 



How nature brings about thefe great 

 changes, is difficult to fay. The moft 

 plaufible and general theory is, that the 

 minute particles of air, of which there is 

 great plenty inclofed in all bodies, extrica- 

 ting themfelves from the fibres of the ve- 

 getable, which is now foftened by moifture, 

 and being agitated by the heat and conti- 

 nual alterations in the preffure of the at- 

 mofphere, raife an inteftine motion in the 



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