AMMONIUM SALTS 165 



than sodium sulphate, and this is found to be the case in 

 practice. 



From what has been said above it will be obvious that it 

 is not possible to describe the actions of all the compounds of, 

 say, a metal under one head, for the acid ion may be the 

 predominant partner, as for example, in the cases of potas- 

 sium cyanide and potassium bromide. Again the physical 

 behaviour of a compound is often of as great importance as 

 its chemical constitution. Thus a strict chemical classifica- 

 tion of drugs is not of any value as a guide to their actions. 

 The chemical and the physical properties of the drug and the 

 vital reaction of the body towards it constitute the specific 

 action of that agent and this must be determined for each 

 individual agent and to some extent for each kind of 

 animal. 



AMMONIUM AND ITS MEDICINAL COMPOUNDS 



AMMONII CHLORIDUM. Sal-ammoniac. Chloride of Am- 

 monium. NH 4 Cl. 



This salt, from which most ammonium compounds are 

 derived, may be formed by neutralising crude solution of 

 ammonia or ammonium carbonate with hydrochloric acid, 

 and purifying the product (B.P.). The salt thus prepared 

 occurs in inodorous colourless crystals, or in translucent, 

 tough, fibrous masses. It has a saline, acid taste, a slightly 

 acid reaction ; is soluble in one part boiling, or three of cold 

 water, and in 60 parts alcohol (90 per cent.). During solu- 

 tion it abstracts much heat, and is consequently an ingred- 

 ient of many freezing mixtures. Heated it sublimes un- 

 changed. Mixed with lime or potash it evolves ammonia. 



ACTIONS AND USES. Expectorant, diuretic and refriger- 

 ant. Large doses, injected intravenously or subcutaneously, 

 exhibit the stimulant and subsequent paralysing effects of 

 ammonium salts. Given by the mouth, two ounces admin- 

 istered to a horse caused muco-enteritis (Moiroud) ; two 

 drachms destroyed a small dog in an hour. The alimentary 

 mucous membrane was found congested and swollen (Orfila). 

 The symptoms described as occurring in dogs are muscular 



