406 MATERIA MEDICA 



muriatic. Of the vegetable only two, — viz. the acetic, or acetous 

 acid, commonly named vinegar; and the tartaric acid, or rather 

 the combination of it, with a small proportion of potash, which 

 is named cream of tartar : no other acids are employed. 



Acid, Acetous or Acetic. — Aciduyn Aceticum. A strong 

 acetic acid is now very commonly obtained from wood, by dis- 

 tillation in iron cylinders. When all the acid and other volatile 

 parts have been expelled, there remains in the iron cylinder the 

 best kind of charcoal. The liquid is at first very impvu-e, and 

 commonly named pyroligneous acid, but by another process it is 

 purified, and becomes a pure and powerful acetic acid. It has 

 of late been much used for medical as well as culinary purposes. 

 Strong acetic or pyroligneous acid is about six times the 

 strength of common vinegar. It is very iiseful and convenient 

 for veterinary purposes, either as a rubefacient, an antiseptic, or 

 an ingredient in cooling lotions. For veterinary purposes, 

 common vinc«:ar will do very AvelL Hot vineo;ar is sometimes 

 used as a fomentation for deep-seated strains: it is used also 

 with water as a cooling lotion ; sometimes it is employed with 

 the addition of crude sal ammoniac (muriate of ammonia) and 

 sjiirit of Avine ; it is seldom given internally. Mr. James Clark 

 relates a case of a horse dying immediately after being drenched 

 with a pint of vinegar. Combined with water it forms an ex- 

 cellent lotion for washing out small particles of lime from the 

 eye. 



Acid, Muriatic. (New name. Hydrochloric Acid.) — 

 Aciclum Hydrochloricum. Commonly called spirit of salt. This 

 is sometimes used externally as a cavistic, and is an excellent 

 agent in neutralising putrid miasmata. When united Avith 

 earths, alkalies, or metallic oxides, it forms muriates. Muriatic 

 acid is now denominated hydrochloric acid, the real acid con- 

 tained in the liquid jireparation being composed of equal volumes , 

 of chlorine and hydrogen. On exposure to the air it emits 1 

 fumes, which are readily seen. It has been given with advantage 

 in cases of calcidi, in doses of one drachm to three in a pint of 

 water, and continued for some time. Its effect is to soften and 

 even dissolve the calcareous body. 



Acid, Nitric and Nitrous. — Acidum Nitricum et Nitrosum. 

 Both these are powerful caustics. The first is limpid or colour- 

 less, and transparent like water ; the nitrous acid is of a dark 

 yellow colour, and gives off suffocating fumes of a deep yellow 

 colour on opening the bottle in which it is kept. This acid is 

 obtained by the action of sulphuric acid on nitre. Some useful 

 external applications are made from nitrous acid, esjoecially 

 nitrate of silver or lunar caustic, and nitric oxide of mercury or 

 red precipitate. Sweet spirit of nitre, now named spirit of 

 nitrous ether, is made by the distillation of nitric or nitrous acid 



