360 ALKALIES AND ALKALINE EARTHS 



into soluble salts in the stomach and exert a purgative action which 

 has been discussed previously. Magnesia is often useful in indi- 

 gestion of young animals with tympany and diarrhea. It may 

 be given in the form of the compound rhubarb powder or with 

 equal parts of rhubarb and magnesia and half as much ginger. Be- 

 sides its antacid and laxative action, magnesium enters into the well 

 known arsenic antidote — Ferri Hydroxidum cum Magnesii Oxido. 

 Magnesium should not be given over a long period of time as it is 

 said to be liable to cause intestinal concretions. 



AMMONIA AND AMMONIUM 



The action of ammonium and its salts differs exceedingly from 

 the previously discussed alkalies. Externally the solutions of am- 

 monia and the gas are very irritant but they are not so corrosive as 

 the hydrates of the other alkalies. 



The characteristic action of the ammonium ion when given sub- 

 cutaneously or intratracheally is stimulation of the central nervous 

 system which is followed by depression after large doses. Keflex 

 irritability is increased and convulsions may take place. The heart 

 and respirations are stimulated reflexly due to the irritant action of 

 the drug. The ammonium ion also increases the secretions, especially 

 the saliva, mucus and sweat. The diaphoretic action is believed to 

 be of central origin while the action on saliva and mucus may be ac- 

 counted for by: 1. Reflex stimulation of the mucosce due to irrita- 

 tion of the mucous membrane of the mouth. This action is impor- 

 tant on account of the fact that the salts of ammonium are some- 

 what eliminated by the saliva, into the mouth and thus produce their 

 local action a second time. 2. Direct stimulation of the secretory 

 center. 



AMMONIA 



This is a colorless gas, very pungent in odor, and possessing an 

 acrid taste. It is obtained as a by-product in the manufacture of 

 coal gas. It is only used in solution. 



Preparations. 



Aqua- Ammonice. Ammonia Water. 



Ammonia water is a solution containing not less than 9.5 per 

 cent, nor more than 10.5 per cent, of ammonia in water. 



Doses. H. 3 j— iv; 4.— 16. D. TTL ij— xv; 0.13—1. 



Aqica Ammonice Fortior. Stronger Ammonia Water. 



Stronger am m onia water is an aqueous solution of ammonia 

 which should contain not less than 27 nor more than 29 per cent. 

 of ammonia. 



