340 CHROMIC ACID 



33'7 per cent, of water. Prepared by treating, with water 

 and nitric acid, the residue left after burning phosphorus 

 in air (B.P.). Specific gravity 1*5. It is a colourless, sour, 

 syrupy liquid, with an acid reaction. In diluted solution 

 it gives, with ammonia-silver nitrate, a canary-coloured 

 precipitate, soluble in ammonia and dilute nitric acid. The 

 acidum phosphoricum dilutum contains 13-8 parts of hydro- 

 gen orthophosphate and 86*2 parts of water. It is a colour- 

 less liquid of specific gravity 1*08. 



Compared with the other mineral acids it is less corrosive, 

 but it may be used for many of the purposes for which nitric 

 and hydrochloric acids are employed. Internally, phos- 

 phoric acid is believed to be less apt to derange digestion 

 when prescribed for a considerable time. In human medi- 

 cine it has been given in diabetes and various cachectic con- 

 ditions, to supply a supposed deficiency of phosphates, but 

 with little success. In canine practice it is sometimes useful 

 in the convalescent stage of distemper. Doses (dilute acid), 

 horses and cattle, 3J- to 3J V - "> sheep and pigs, ll\xxx. to 

 3J. ; dogs, 11\v. to n\xxx. 



CHROMIC ACID 

 CHROMIC ANHYDRIDE (Cr0 3 ). 



Acidum chromicum produced by the interaction of sul- 

 phuric acid and potassium bichromate, occurs in crimson, 

 deliquescent, needle-shaped crystals, and is very soluble 

 in water and in ether. The liquor acidi chromiei is made 

 with one part of acid and three of water. It readily parts 

 with oxygen, oxidises organic matter, coagulates albumin, 

 destroys low organisms, and decomposes ammonia and sul- 

 phuretted hydrogen, and though not prescribed internally, 

 it is used as a caustic, antiseptic, deodoriser, and disinfec- 

 tant, and to harden the replacing horn after operations on 

 the horse's foot. In the treatment of ' canker,' Sheather 

 has been very successful with pure chromic acid applied on 

 carbolised cotton wool. For snake-bites, Kaufmann recom- 

 mends the injection round the wounds of four or five drops 

 of a one per cent, solution of chromic acid. 



