414 POISONS, CONTAGIONS, MIASMS. 



plex molecules ; even the presence of any body the 

 particles of which are undergoing motion or trans- 

 position, is often sufficient to destroy their state of 

 rest, and to disturb the statical equilibrium in the 

 attractions of their constituent elements. An imme- 

 diate consequence of this is, that they arrange them- 

 selves according to the different degrees of their 

 mutual attractions, and that new compounds are 

 formed in which chemical affinity has the ascendancy, 

 and opposes any further change, while the conditions 

 under which these compounds were formed remain 

 unaltered. 



