CHEMISTRY 207 



acid, oxalic acid, acetone, ether, lactic acid, 

 sugar, cotton, glycerine, olive oil, camphor, 

 tannin, ophiotoxin (the chief poisonous con- 

 stituent of cobra venom), starch, vanilline 

 (the flavoring constituent of the vanilla bean), 

 oil of wintergreen, salol, benzoic acid, digita- 

 line. 



Here is a variety that baffles description ; 

 but description is hardly necessary, for the 

 facts explain themselves. In short, the com- 

 pounds of the three elements which compose 

 water and carbon dioxide exist in enormous 

 numbers and in unparalleled diversity of chem- 

 ical and physical characteristics. They in- 

 clude substances of the greatest stability, and 

 others of exceeding instability ; liquids, solids, 

 and gases ; chemically active and chemically 

 inert bodies ; acids and neutral substances ; 

 substances which are readily oxidized and 

 others which are oxidized only with great 

 difficulty. In a very large proportion of 

 cases these compounds are capable of enter- 

 ing into reactions with one another. They 

 are, moreover, capable of forming still more 

 complex substances, in still greater variety 

 by entering into union with other elements, 

 notably with nitrogen and sulphur. 



