MEDICIXES.] 



THE HOESE. AFD 



[medici>"es. 



Pix NiGEA— JBZ«c/j FitcJi. 



This is the residue in the retort after the 

 distillation of the oil from tar. 



Medicinal Uses. — Slightly stimulant, and 

 adhesive; but seldom used. 



Pix Liquida — Tar. 



This is obtained by placing billets of the 

 Scotch fir in large stacks, which are closely 

 covered with turf, and to whicli fire is then ap- 

 plied. They are suffered to burn with a slow, 

 smothered flame ; during which time tar is 

 formed by the decomposition of the resinous 

 juice of the wood, which flows to the bottom, 

 and runs out at a small channel cut for the 

 purpose. 



Medicinal Uses. — Stimulant applied exter- 

 nally, entering into the composition of Unguen- 

 tum Ficis Liquida. Melted with an equal 

 quantity of grease it makes the common stop- 

 ping of the farrier, and is extremely useful 

 for dressing bruised or wounded feet. Its 

 chief value, however, in veterinary practice 

 does not arise from its keeping out dirt and 

 water from the wounded part, but from its mol- 

 lifying influences on the horse itself, making 

 the part more elastic, yet softer, and less 

 likely to break away. It is the proper basis 

 of thrush ointment, and is also used as an 

 ingredient in the applications for mange. The 

 spirit of tar, combined with double the quan- 

 tity of fish oil, is one of the very best appli- 

 cations that can be made to hard and brittle 

 feet. Tar is sometimes given in doses of two 

 or three drachms, in cases of chronic cough. 



Plumbi OxTDUii Semivitium — Semivitrijied 

 Oxide of Lead — Litharge. 



Lead is a white metal of a considerably blue 

 tinge ; very soft and flexible ; not very tenacious. 

 Its sp. gr. is 11-35. It melts at 612 deg. 



This oxide of lead is prepared by the action 

 of heat and air upon the metal. The lead is 

 placed upon a warm furnace in a hollow dish 

 made of ashes, and kept at a red heat with the 

 blast of a large pair of bellows directed on its 

 surface. An oxide soon appears, and is suc- 

 cessively formed by rakiug it, and exposing it 

 to a new surface. 



All the oxides of lead are easily revived 

 with heat and carbon. Oxygen and lead com- 

 358 



bine together in difierent proportions. If the 

 nitrate of lead be dissolved in a precipitation 

 produced by potash, the precipitate, when 

 dried, will become the yellow protoxide. If it 

 be somewhat vitrified, it constitutes litharge : 

 and combined with carbonic acid, it becomes 

 white lead, or ceruse. Lead, alloyed with an 

 equal weight of tin, ceases to be acted upon by 

 vinegar. Acetate and sub-acetate of lead have 

 a good eftecfc, as external applications, for in- 

 flamed surfaces, burns, scrofulous sores, and as 

 eye-washes. Lead, taken internallv. is very 

 injurious ; hence the diseases to whl,_ painters 

 are liable. Litharge, dissolved in wines, to 

 give them a sweet taste, is very mischievous. 

 Sulphuretted hydrogen will cause it to throw- 

 down a black precipitate. 



Medicinal Uses. — In making the \\c^ov plumhi 

 suj^eracetatis. Eor the deleterious effects pro- 

 duced upon animals in the neighbourhood of 

 lead works, active purgatives, followed by opium, 

 are the most efi'ective remedies 



Plumbi Supeeacetatis — Superacetate of 

 Lead. 



Take of Carbonate of Lead » 1 lb. 



„ Acetic Acid . . . 1| gallon. 



Boil the carbonate of lead with the acid until it 

 is saturated, then filter it through paper, and 

 evaporate it until a pellicle appears. Set it 

 aside to crystallise from off the super natant 

 born fluid, and dry the crystals on blotting- 

 paper. 



Medicinal Uses. — Cooling, applied externally 

 in the form of solution, for inflammation of the 

 eyes. Goulard's ointiDent, however, is a better 

 preparation for external and superficial inflam* 

 mation. 



PoTASSiE NiTEAS — Nitrate of Fotasli — Nitre, 



Nitre is the common name of the nitrate of 

 potash. It is known by the name of saltpetre, 

 and is found ready formed in the East Indies, 

 in Spain, in the kingdom of Naples, and else- 

 where, in considerable quantities ; but nitrate 

 of lime is still more abundant. Far the 

 greater part of the nitrate made use of, is pro- 

 duced by a combination of circumstances 

 which tend to compose and condense nitric 

 acid. This acid appears to be produced in all 

 situations where animal matters are completely 

 decomposed through the action of air upon 



