ORGANIC STRUCTURE: CHEMICAL 23 



yd. The Characteristic Elements in Organic and In- 

 organic Things. Simplifying the matter by regarding water 

 as the immediate medium in which both organic and in- 

 organic chemical substances react we find these elements to 

 be those characteristic of the two great classes of natural 

 things : 



Inanimate things : Oxygen, silicon, aluminium, iron, calcium. 



Organisms : Carbon, nitrogen, hydrogen, oxygen. 



8. ON THE CHEMICAL COMPOUNDS THAT COMPOSE 

 THE BODIES OF ORGANISMS 



First we consider the chemical compounds that make up in- 

 organic things. A cursory survey of the field of inorganic chemis- 

 try shows very different kinds of chemical categories than we find 

 in the bodies of organisms. 



Sa. Inorganic Chemical Categories. First, then, the 

 elementary substances : 



Metals — (iron, nickel, copper, etc.) inferred to be present in 

 the heated centrosphere, or " kernel " of the earth. Noble metals 

 (gold, platinum, etc.) present in small quantities in the rocky 

 crust ; 



Non-metals — Sulphur, hydrogen, etc., present in volcanic 

 emanations ; oxygen, nitrogen, argon, helium, etc., present 

 in the atmosphere. 



Second. There are the characteristic mineral substances of the 

 earth's crust : 



Silica, silicates of aluminium and the alkaline and earthy 

 metals ; 



Carbonates (of lime, magnesia, etc.) ; oxides (such as those 

 of iron) ; sulphides (iron pyrites, for example) ; phosphates (such 

 as apatite) and so on ; 



The water of the ocean, of ice and snow and of lakes and 

 rivers ; the water and carbon dioxide of the atmosphere and 

 so on. 



Chemically these categories of natural things are structurally 

 simple ; thus 



Water— H — O - H 

 Carbon dioxide — O = C = O 

 Silica— O = Si = O 



But this simplicity, as it is represented above, is fictitious.: 



