132 MATERIA MEDIC A AND THERAPEUTICS. 



higher salts. The suggested decomposition of hyposulphites 

 into sulphites and free sulphur, and their consequent alterative 

 and disinfectant action in phthisis and other diseases, appear 

 to he equally unreal. 



3. REMOTE LOCAL ACTION. 



Sulphites are excreted hy the urine and howels in the form 

 of sulphates. 



Acidum Nitrosum. Nitrous Acid. HN0 2 . (Not 



linal.} 



This acid is not itself used in medicine, hut the nitrites are 

 active and valuable drugs. Those in use are nitrite of sodium 

 and nitrite of amyl, as well as sweet spirit of nitre and nitro- 

 glycerine. The sodium salt will be noticed here ; the others 

 under their own heads. 



Sodii Nitris. Nitrite of Sodium. NaN0 2 . (Not Officinal.} 



Source. Made by heating nitrate of soda. 2NaN0 3 2Na 

 N0 2 + 2 . 



Characters. A white granular powder, deliquescent, with a 

 cool saline taste, very soluble in water. 



Impurities. The nitrate, and caustic soda. 



Dose. 2 to 10 grains. 



ACTION AND USES. 



Nitrite of sodium acts upon the blood, the heart, and vessels 

 like nitrite of amyl, only less suddenly and markedly, and for a 

 much longer period of time. It has been used with success in 

 heart disease, with recurrent attacks of painful angina ; less 

 successfully in epilepsy. Its depressant action on the central 

 nervous system is more marked than that of the amyl compound ; 

 and it also paralyses the peripheral nerves and the muscles 

 not only in this way, but through the blood. 



GROUP V. 



WATER. 



AQUA. WATER. 



Natural water, the purest that can be obtained, 

 cleared, if necessary, by filtration, and free from 

 odour, taste, and visible impurity. 



