36 VETERINARY MATERIA MEDICA. 



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, H3PO,. 

 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 of 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- 



