DISSOLUTION. 537 



which accompany variations of temperature. All know that 

 in cool weather the organic substances used in our housQ- 

 holds keep longer, as we say, than in hot weather. Equally 

 certain, if less familiar, is the fact that in tropical climates 

 decay proceeds much more rapidly than in temperate cli- 

 mates. Thus, in proportion as the molecular motion of 

 surrounding matter is great, the dead organism receives an 

 abundant supply of motion to replace the motion continually 

 taken up by the dispersing molecules of the gases into 

 which it is being disintegrated. The still quicker 



decompositions produced by exposure to artificially-raised 

 temperatures, afford further proofs ; as instance those which 

 occur in cooking. The charred surfaces of parts that have 

 been much heated, show us that the molecular motion ab- 

 sorbed has served to dissipate in gaseous forms all the ele- 

 ments but the carbon. 



The nature and cause of Dissolution are thus clearly dis- 

 played by the aggregates which so clearly display the na- 

 ture and cause of Evolution. One of these aggregates being 

 composed of that peculiar matter to which a large quantity 

 of constitutional motion gives great plasticity, and the abil- 

 ity to evolve into a highly compound form ( 103) ; we see 

 that after evolution has ceased, a very moderate amount 

 of molecular motion, added to that already locked up in 

 its peculiar matter, suffices to cause dissolution. Though 

 at death there is reached a stable equilibrium among the 

 sensible masses, or organs, which make up the body; yet, 

 as the insensible units or molecules of which these organs 

 consist are in unstable equilibrium, small incident forces 

 suffice to overthrow them, and hence disintegration pro- 

 ceeds rapidly. 



180. Most inorganic aggregates, having arrived at 



dense forms in which comparatively little motion is retained, 



remain long without marked changes. Each has lost so 



much motion in passing from the disintegrated to the inte- 



36 



