THE ASSOCIATIONS OF CHEMICAL ATOMS. 



In their individuality ; but In the complexity of the 

 physical systems of associated particles, the fact 

 which here corresponds to the development of social 

 complexity, we can trace a gradual evolution. 



§ 16. Of all chemical compounds, the so-called 

 organic compounds are the most complex, i.e.^ they 

 contain and unite the largest number of Individual 

 molecules. They are thus the most highly organized 

 forms of matter. And they are also the most 

 recently evolved. For a comparatively slight degree 

 of heat will break them up, or, as chemists say, with 

 a significant suggestion of the social character of 

 chemical combination, will dissociate them. Hence 

 they cannot have been formed until the earth had 

 cooled considerably. And yet their appearance 

 must have preceded that of living matter, as they 

 supply the basis of the higher evolution of the 

 animate. Thus the organic compounds represent 

 the highest form of chemical combination, not only 

 because they are the basis of living organisms, but 

 also because they are evolved later. 



Taking next the Inorganic compounds we find 

 that they are on the whole less complex and more 

 stable than the organic. But though they can 

 stand a higher degree of heat, they are yet dissoci- 

 ated at high temperatures. Hence they stand lower 

 In the scale of evolution, and if the nebular theory 

 may be trusted, they are also, historically speaking, 

 more ancient. 



The chemical *' elements " again are *' simple " 

 bodies which we have not hitherto been able to dis- 

 sociate. And yet, under the delicate manipulations 

 of modern chemistry, and In the terrific temperatures 

 of the hottest stars, they also betray signs of dis- 

 sociation (cf. ch. vli. §§ 10, 11). And as was shown In 



