AMMONIUM. 45 



yellow by exposure to the air, and have a pungent saline 

 taste. Solubility, 1 in 1^ of water. 



Impurities. Iodides ; free bromine. Detected by colour. 



Dose. 2 to 20 gr. 



ACTION" AND USES. 



1. IMMEDIATE LOCAL ACTION AND USES. 



Externally applied, ammonia is a stimulant to the nerves 

 and other structures, causing a sensation of pain and burning, 

 and reddening the part by dilating the vessels. If the appli- 

 cation be prolonged and the vapour confined, blistering may 

 result ; but dilute preparations produce only a rubefucu-nt 

 effect and a sense of heat. It is used in the form of liniment to 

 stimulate the circulation in a part, either for the purpose of in- 

 creasing the local nutrition (for instance, in stiffness or other 

 chronic conditions of joints), or as a counter-irritant (see Part 

 III.) in diseases of deeper parts, e.g. on the surface of the chest 

 in bronchitis. Ammonia is not to be used as a caustic ; and 

 vesication by it is better avoided. In serpent's bite, the appli- 

 cation of ammonia to the wound has occasionally saved life. 



Internally. Admitted into the nose, ammonia itself, or the 

 vapour of the carbonate ("smelling salts"), is a powerful 

 general stimulant, instantly causing a pungent sensation, 

 sneezing and other disturbances of the respiration, acceleration 

 of the pulse, and watery secretion from the parts including 

 the conjunctiva. It is accordingly used as a means of resus- 

 citating consciousness, the action of the heart, and respiration, 

 in cases of failure of the circulation, such as fainting, or of 

 asphyxia. 



In the stomach, ammonia produces the same effects as on 

 the skin. A full dose (30 gr. of the carlxm.itr well diluted) is 

 an emetic, which is best used in croup and bronchitis. Smaller 

 doses cause a sense of warmth at the epigastrium, and act as 

 carminatives, sal-volatile being chiefly used for this purpose. 

 In common with soda and potash, it has an antacid effect on 

 the contents of the stomach, and may be given after meals in 

 dyspepsia. Like these, also, it acts as a natural stimulant to 

 the gastric juice before meals, and sal- volatile is therefore a 

 common ingredient of alkaline stomachic mixtures. On the 

 bowels, ammonia appears to have no local action. 



2. ACTION ON THE BLOOD, AND ITS I 



Ammonia is absorbed into the blood, and is there fixed ; in- 

 creasing, possibly, the alkalinity of the plasma, and diminishing 



