52 THE THEORY OF IONS 



and join it to form a chain. These are straight or 

 open chains and cylo or closed chains or rings, of 

 which examples are here given. If H atoms are 

 removed from the ends of the straight chain, and 

 the free valencies of the carbon are not satisfied 

 by union with another ion, they bend over until 

 they meet and form a ring. Side chains are formed 

 by another radical or rest dislodging one or more 

 H atoms from such a ring. H is represented by the 

 open circle and C by the closed one. 



6 6 



Hexane, C 6 H 14 



9 



* 



o. 



6 666 



Benzene-hexa- Cyrnene-hexa- 



hydride, C 6 H 12 hydride, C 10 H 20 



The importance of ions in the physiological 

 economy of plants and animals is strikingly evident. 

 Animals are dependent, herbivora directly and carni- 

 vora indirectly, upon plant life for the chief elements 

 of their sustenance, viz., proteins, carbohydrates and 



