MEDICINES.] 



THE HOESE, AJTD 



[medicines. 



of potash, from which it is expelled by sulphu- 

 Iric acid. 



Take Dried Nitrate of Potash . 2 lbs. 

 „ Sulphuric Acid (by weight) 2 „ 

 Mix them in a glass retort ; distil the Ditric 

 acid off by means of a sand bath, till a red 

 vapour arises ; then having added another 

 ounce of the dried nitrate of potash, continue 

 the distillation. When these are heated toge- 

 ther, a double decomposition takes place. The 

 dry sulphuric acid unites to the potash, and 

 forms sulphate of potash of what remains in 

 the retort; whilst the nitric acid disengaged, 

 unites with the water, rising in the state of 

 vapour: these become condensed in the re- 

 ceiver, and form liquid nitric acid. 



Medicinal Uses. — Caustic and stimulant ; as 

 the former, it is applied alone ; as the latter, 

 in combination with tar. It destroys all 

 fungous excrescences by deadening them, and 

 making them slough off. 



AciDUM Htdeocianicum — Priissic Acid. 



JPriissic acid, in chemistry and the arts, is 

 one of the most important of the acids. It 

 was discovered by accident about the be- 

 ginning of the last century, by Diesbach, a 

 chemist of Berlin. This gentleman, wishing 

 to precipitate a decoction of cochineal with 

 an alkali, got some potash on which he had 

 distilled several times his animal oil ; and as 

 there was some sulphate of iron in the de- 

 coction, the liquor instantly exhibited a beau- 

 tiful blue in the place of a red precipitate. 

 Hence he saw the method of producing the 

 same substance at pleasure ; and it soon be- 

 came an object of commerce, and obtained 

 the name of Prussian blue, from the place 

 where it was discovered. This substance is 

 now formed, chiefly, during the decomposi- 

 tion of animal substances in high tempera- 

 tures. In a concentrated state it is a deadly 

 poison, and a few drops of it will kill a large 

 animal. 



Medicinal Uses. — A powerful sedative, and 

 admirable in ahaying the excitement of the 

 rervous system, "In doses of six drops," 

 says Mr. Touatt, "largely diluted, it abates 

 both pulmonary and gastric irritation. It 

 may be worth trying in the form of enema, in 

 cases of letanus. It may also be given by 

 the mouth in the same disease. The author of 

 348 



this work was the first who applied the hydro- 

 cyanic acid, for the purpose of allaying irrita- 

 tion of the skin in dogs. It seldom fails of 

 producing the desired effect, and is similarly 

 effective in subduing itchiness and mange in 

 the horse." 



AciDUM .SiTLPHURicuM — Sulpliuric Acid — 

 Oil of Vitriol. 



Sulphuric acid is generally procured by burn- 

 ing a mixture of sulphur and nitre in chambers 

 lined with lead. The sulphur burning in the 

 atmospheric air of the chamber, forms sulphu- 

 ric acid gas. The nitre gives rise to the nitric 

 oxide, which, with the oxygen of the air, pro- 

 duces nitrous acid gas. These two gases, 

 from the moisture present, form a white solid, 

 which is instantly decomposed in the water, 

 when the nitrous acid reverts to the state of 

 nitre oxide, having transferi-ed one additional 

 proportion of oxygen to the sulphureous acid, 

 forming sulphuric acid, which uniting with the 

 water, forms liquid sulphuric acid. It is a 

 liquid somewhat of an oily consistence, trans- 

 parent and colourless as water, without any 

 smell, and of a very strong acid taste. AVhen 

 applied to animal or vegetable substances, it 

 very soon destroys their texture. 



Medicinal Uses. — Caustic and stimulative, 

 applied externally, but not very often used 

 alone, entering more into combinations. 



Alumina et Potassje Super Sulphas — 

 Super Sulphate of Alum and Fotash. 



This is a salt of alum. Potash and sulphu- 

 ric acid are found native in some places ; but 

 the greater quantity of the alum used in com- 

 merce is prepared from alum ores. By ex- 

 posing these to atmospheric air, the oxygen 

 unites to the sulphur of the sulphuret of iron 

 present, and becomes converted into sulphuric 

 acid, and then combining with the alumine, 

 the alum effloresces. This is subsequently 

 evaporated, and then set aside to crystallise. 



Medicinal Uses. — Astringent ; this is only 

 used for the horse as an external application 

 in the formula. 



AcoNiTi PoLiA — Leaf of Aconite, or Monk''s 

 Hood. 

 This is a perennial plant, cultivated in our 

 gardens, flowering in June, but found native 



