ALKALINE ALTERATIVES. 157 



what rapid oxidation under the influence of alkalies, the tendency 

 of their constituent carbon to become oxidised, otherwise inferior 

 to that of their constituent hydrogen, becoming intensified, appa- 

 rently because of the opportunity afforded by the presence of the 

 alkali for the formation of salts instead of acids. 



(164.) Be the explanation, however, what it may, the fact is 

 unquestionable, and readily admits of experimental illustration. 

 For instance, I have in this porcelain dish the watery solution of 

 a substance well known to photographers as pyrogallic acid, 

 though its acidity is of such a feeble character that it is nowadays 

 more frequently spoken of by chemists under the neutral appella- 

 tion of pyrogallin. At present, the solution in the dish, though 

 exposed freely to the air for upwards of an hour, has not under- 

 gone any appreciable oxidation. I now moisten the interior of 

 this long tube with a little aqueous potash, and invert it in the 

 solution, when the commencing oxidation of the dissolved pyro- 

 gallin is manifested to you by its almost immediate assumption 

 of a brown-black colour, followed by the gradual rising up of the 

 black liquid in the tube, through an absorption of the oxygen of 

 the contained air. The pyrogallin, which did not become oxi- 

 dised in any appreciable degree so long as there was no alkali 

 present, now becomes oxidised with considerable rapidity, as you 

 observe, yielding among other products acetate, oxalate and car- 

 bonate of potassium. Other familiar illustrations of this action 

 of alkalies are afforded us in the employment of lime to promote 

 the destructive oxidation of dead bodies, and as a manure to de- 

 stroy the organic matter of peaty soils. Some very interesting 

 results have also been obtained by Gorup-Besanez, who found 

 that glycerin, sugar, leucine, hippuric acid, oxalic acid, and the 

 fatty and aromatic acids, which of themselves were unacted upon 

 by ozonised air, underwent a very complete oxidation when sub- 

 mitted to the same reagent in the presence of caustic or even 

 carbonated alkali. Benzoic acid, for instance, which results from 

 the violent oxidation of animal matter, and consistently resists the 

 action of very powerful oxygenants, undergoes a complete and 

 somewhat speedy oxidation when submitted in alkaline solution 



