36 VETERIN^AET MATERIA MEDICi.. 



aqua regia. This is a mixture of the nitric and hy- 

 drochloric acids, but in its full strength is used only 

 in the arts. 



Phosphoric Acid, acidum phosphoricum, HjPO^. 

 Concentrated phosphoric acid is obtained by heating 

 phosphorus with dilute nitric acid until nitrous fumes 

 no longer come off ; the resulting compound is then 

 diluted with water till its specific gravity is 1.5. It 

 requires about thirty-three per cent, of water. Con- 

 centrated phosphoric acid is a clear, colorless, acid, 

 syrupy liquid, and in its purity is not used medicin- 

 ally. 



Physiological Actions op the Mineral Acids. 



The strong acids are corrosive irritant poisons if 

 given internally, unless properly diluted and in proper 

 quantity. Medicinal doses are refrigerant, antisep- 

 tic, tonic, and astringent. Externally: Stimulant, 

 astringent, and escharotic. They abstract water 

 from the tissues, combine with bases to form salts, 

 destroy protoplasm, and are very diffusible. Sul- 

 phuric acid carbonizes (black) ; nitric acid tans (yel- 

 low) . When in contact with the mouths of ducts 

 having an alkaline secretion this is produced in in- 

 creased quantity, while if in contact with the mouths 

 of ducts having an acid secretion this latter is de- 

 creased. Secretion in general is promoted by nitric 

 acid, and decreased by sulphuric acid — nitric acid 

 aiding peristalsis, sulphuric acid producing constipa- 

 tion. Muriatic acid aids digestion and stimulates 

 mucous and intestinal secretions, especially when com- 



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