ACTION OF ACIDS 253 



sion of proteids into peptones by pepsin, and in stimulating 

 the formation of the latter. Mineral acids are essentially 

 digestive tonics, promoting gastric digestion (H CI), increas- 

 ing the secretion of the liver and intestinal glands, and 

 improving the tone and blood supply of relaxed intestinal 

 mucous membrane. 



Constitutional Action. — Acids are absorbed, and in consi- 

 derable doses make the blood less alkaline, the urine more 

 acid, and appear to exert a slight astringent action upon the 

 skin and mucous membranes during their elimination. We 

 possess no knowledge to explain the remote effects of the 

 acids. Some authorities state that the acids are converted 

 into salts in the blood, as sulphates, nitrates and phosphates, 

 which are eliminated by the urine, skin and bowels. Others 

 teach that much of the acid is eliminated in th^ urine in the 

 form of ammonia compounds. Brunton says that the acids 

 cause a modification of tissue change in the liver so that the 

 production of urea is lessened by the passage of the acids 

 through that organ, and that the ammonia furnished by the 

 acids is not converted into urea, as normally happens, but 

 is eliminated in the urine as such. Both these suppositions 

 are apparently fallacious, because if the acids were trans- 

 formed into salts they would not produce remote astringent 

 effects^ and if they were converted into ammonia compounds 

 they would not acidify the urine. The probable explana- 

 tion is that in small doses acids are more prone to decom- 

 position, while large doses are eliminated in part unchanged 

 by the kidneys, bowels and skin, and so acidify the urine 

 and exert a remote astringent action. 



Acidity of the blood causes death in depressing the 

 heart, and because an alkaline or neutral medium (normal 

 blood) is essential to carry away carbonic dioxide from the 

 tissues. Vegetable acids are thought more especially to 

 lower the force of the heart, which they certainly do in 

 poisonous quantities, and possibly in medicinal doses. In 

 considerable amount, the vegetable acids increase the acidity 

 of the urine, but in small doses alkalize this secretion by 



