632 POISONS : THEIR EFFECTS AND DETECTION. [§§ 807 - 809 . 
into the carbonate of lead by boiling it with solutions of the alkaline 
carbonates. The sulphate of lead, fused with cyanide of potassium, 
yields metallic lead ; it may be also reduced on charcoal, and alone 
it may be fused without decomposition, provided reducing gases are 
excluded. 
§ 807. Acetate of Lead, Sugar of Lead, Pb(C 2 H 3 0 2 ) 2 30H 2 =379, 
is found in commerce in white, spongy masses composed of acicular 
crystals. It may, however, be obtained in flat, four-sided prisms. 
It has a sweet, metallic taste, is soluble in water, and responds to the 
usual tests for lead. The B.P. directs that 38 grains dissolved in 
water require, for complete precipitation, 200 grain measures of the 
volumetric solution of oxalic acid, corresponding to 22-3 grains of 
oxide of lead. 
§ 808. Chloride of Lead, PbCl 2 =278—specific gravity, 5*8; Pb 
74-48 per cent. ; \21 25-52 per cent.—is in the form of brilliant crystalline 
needles. It is very insoluble in cold water containing hydrochloric or 
nitric acid. According to Bischof, 1635 parts of water containing nitric 
acid dissolve one part only of chloride of lead. It is insoluble in absolute 
alcohol, and sparingly in alcohol of 70 to 80 per cent. It fuses below 
red heat without losing weight ; at higher temperatures it may be 
decomposed. 
Carbonate of Lead. —The commercial carbonate of lead (according 
to the exhaustive researches of Wigner and Harland x ) is composed of a 
mixture of neutral carbonate of lead and hydrate of lead, the best 
mixture being 25 per cent, of hydrate, corresponding to an actual 
percentage of 12-3 per cent, carbonic acid. The nearer the mixture 
approximates to this composition the better the paint ; whilst samples 
containing as much as 16-33 per cent., or as little as 10-39 per cent., of 
C0 2 are practically useless. 
§ 809. Preparations of Lead used in Medicine, the Arts, etc. 
1. Pharmaceutical:— 
Lead Plaster (Emplastrum plumbi) is simply a lead soap, in which 
the lead is combined with oleic and margaric acids, and contains some 
mechanically included glycerin. 
Lead Iodide, Pbl 2 , is contained in the Unguentum plumbi iodidi to 
the extent of 10 per cent. 
Acetate of Lead is contained in a pill, a suppository, and an oint¬ 
ment. The pill ( Pilula plumbi cum opio ) contains 80 per cent, of 
lead acetate and 12 per cent, of opium, the rest glucose syrup. The 
suppository ( Suppositoria plumbi composita ) contains 20 per cent, of 
acetate of lead and 6-6 per cent, of opium, mixed with oil of theobroma. 
1 “ On the Composition of Commercial Samples of White Lead,” by G. W. Wigner 
and R. H. Harland, Analyst, 1877, p. 208. 
