OF FARRIERY. 



515 



Mix the nitric acid with the water, and dis- 

 solve the silver with the mixture on a sand 

 bath ; then gradually raise the heat until the 

 nitrate of silver becomes dry ; melt this in 

 a crucible over a slow fire until ebullition 

 ceases ; then pour into moulds. 



Decomposition. Nitric acid is composed of 

 oxygen and azote, and when the silver is dis- 

 solved, a portion of the acid is decomposed, 

 its azote escaping into the air with the oxy- 

 gen, which with it forms fumes of red nitrous 

 acid gas. The oxygen of the decomposed 

 acid unites with the silver to form into an 

 oxide, whilst the undecomposed acid dissolves, 

 and converts it into nitrate of silver. 



Medicinal Uses. — Caustic. This appears 

 to have given place to less expensive prepara- 

 tions, such as the nitric acid, and the sulphate 

 of copper 



BOLUS ARMENI/E. 



ARMENIAN BOLE. 



A friable earthy substance of the clay kind, 

 which comes from America. 



Medicinal Uses. — Slightly astringent and 

 absorbent. It is chiefly used for colouring 

 ointments and powders, and for lowering the 

 effect of other active remedies, as sulphate of 

 copper and alum, when used as astringent 

 powders, in case of grease, &c., &c. 



CAMPHORifl. 



CAMPHOR. 



This concrete matter is obtained from the 

 roots and smaller branches of the camphor 

 tree, which grows in Sumatra and Borneo, by 

 distillation ; afterwards it is sublimed into glass 

 vessels with quick lime, and ultimately it is 

 pressed into cakes. 



Medicinal Uses. — Febrifuge, internally ; 



stimulant, externally; in doses of 3J to 3 ij, 

 combined with nitre and tartarized antimony ; 

 as an external application it is used in the 

 compound soap liniment. 



CANTHARIS. 



BLISTERING FLY. 



This fly is found plentifully in Spain, Italy, 

 and France, on several kinds of trees. Those 

 from Spain are obtained by shaking the trees 

 on which they are found, and catching them 

 in a cloth spread underneath. They are then 

 killed by the steam of boiled vinegar, and dried 

 by the sun or stove. The active principle 

 appears to reside in an oil which they contain. 



Medicinal Uses. — Vesicant, applied in the 

 formulee unguentum cantharidis infasium, &c., 

 &c. 



CATECHU EXTRACTUM. 



EXTRACT OF CATECHU. CATECHU. 



This extract, prepared from the inner wood 

 of the tree, which grows in Hindos, by boiling 

 the water, straining the decoction, and after- 

 wards evaporating in the sun. 



Medicinal Uses. — Astringent. Dose from 

 5 ij to 3 iv, in combination with creta preparata. 



CRETA PREPARATA. 



PREPARED CHALK. 



This is made by washing common chalk in 

 water, allowing the grosser particles, as sand, 

 &c., to fall to the bottom, whilst the firm par- 

 ticles floating on the water, is poured off with 

 it into another vessel, and then is allowed to 

 subside, which is afterwards made into nobs 

 and dried. 



3Iedicinal Uses. — Absorbent, anti-acid. It 

 is either given alone, or in combination, with 

 kino, catechu, &c., in quantity from 5 iv to 5 vi, 

 in diarrhoea. 



