110 ORIGIN AND NATURE OF LIFE 



An outline has been given above of the 

 relationships of the sugars and starches. 

 These together form the carbohydrates, those 

 of the fats and proteins may now be considered 

 so far as they come within our line of thought. 



The fats of living cells consist of one group 

 called glycerine, which behaves as a trivalent 

 base united to three huge groups of a uni- 

 valent or monad acid. The glycerine is 

 simply a three carbon chain, in which each 

 carbon atom is united to a hydrogen atom 

 and a hydroxyl group (HO), thus : — 



H H H 



I I I 

 H-C-C-C-H 



! I I 

 OH OH OH 



(Glycerine) 



when the fat is formed in nature, each OH 

 group is replaced by a molecule of the fatty 

 acid. In this process a hydrogen atom is 

 set free to unite with the HO from the glycerine 

 to form water, much as the reduplication of 

 the sugar molecules to form water was seen 

 to occur above. So we have now only to 

 elucidate the nature of this fatty acid which is 

 to combine with the glycerine. If the formula 

 (1) be written down again, with hydrogen 



