10 



LEAD. MEDICAL PROPERTIES OF. 



I.KAK MANUFACTURE. 



MI 



of Isad Into the ijttam it at frequent ooeurrenoe. The 

 toons of UMSS i* UM UM of water or other fluid* con- 

 i ia solution, the intermixture of ld, as adulteration* 

 Dtany. with articls* of food, or handling preparations of 

 Iwd ia U ihlly budosss of artisans, tueh M painters, plumber*, c. 



th duger of using water from leaden pipes or cittern* w.i* known 

 even to UM Roman*, " among whom, however, the reservoir* were 

 itnr of marbi* or reinsnt. or of copper lined with tin. or of other 

 BMtal* more precious- (Aldcnon); nevertheless, pipe* and cistern* of 

 lead are Mill extensively used, and the rarity of any (Mai result* *howa 

 that UM risk ha* been overrated. Thi* I* sufficiently explained by 

 UM protecting power of the insoluble salts of lead, formed by the action 

 el UM ingredient* of the water on the lead, which hinder* the lubeequent 

 supplies of water from coming in contact with the metal [!,F.AD, 

 Col 144.) No water should ever be drunk or employed for culinary pur- 

 pow* out of < ciatern* ; but water tbould be allowed to stand in them 

 lor tome time without being renewed, for only after a cruat has been 

 formed does the water become safe ; or to expedite thin, a little phos- 

 phate of toda or iodide of potaatium may be added, or a few drop* of 

 eulphurio acid may be used. The expedient uf Mr. Chatterton of tin 

 inside lining of gutu percha to pipe* or ciatern* remove* all danger. 

 The lid or oarer of cisterns should never be made of lead, a* the 

 vapour which condense* on it poeseste* all the solvent power of dis- 

 tilled water. It i also unsafe to use water which ha* flowed over 

 Inadon roof*, more particularly in towns, a* the surface of the lead is 

 almost invariably coated with some soluble salt; this Dr. Medlock 

 attributes to nitrous acid being present in the atmosphere of towns. 

 It is, however, an error to attribute all the changes which lend used 

 for roots or cisterns undergoes solely to the corrosive power of 

 water. (See case by Dr. Wall, quoted in Christison, p. 488, edition 

 ISM.t The holee with which the lead is often riddled are caused by 

 the larra of an insect, the Calltdium bajiilut, in the stomach of 

 which load i* often found. ( Kirby and Spenoe's Entowviln y, i.. 

 p. 235.) The I'roetrm jumcta, Linn, and AnMitm flriatnm, likewise 

 perforate lead. 



Perfumed distilled waters, such as orange-flower water, often con- 

 tain lead in solution, derived from the solder cementing the copper 

 vsttsli in which these are imported, whenever lead has been employed 

 instead of tin solder. 



No kind of adulteration or impregnation with lead, from accident or 

 ignorance, is more common than that of wine or cyder. Even a single 

 loot of lead left by accident in a bottle after cleaning has produced 

 severe colic ; and the more extensive use of the salts of lead to fine 

 wines, as it is termed, that is, to remove their acid taste and make 

 them tweet, has occasioned most serious consequences. In the cyder- 

 presns, and in the worm* of stills, lead was formerly employed, but it 

 is now nearly banished from use. Lead is sometimes employed either 

 igoorantly or fraudulently, to render tan and bad wines marketable. 

 The lead, if present, may be detected by appropriate testa, among 

 uthen by Uak*tma*'t tciiu tat, made by putting into a small phial 

 18 grains of sulphuret of lime, prepared in the dry way, and 20 grains 

 of cream of tartar. The phial b to be filled with water, well corked, 

 and occasionally shaken for the space of ten minutes. When the 

 powder ha* subsided, the clear liquor is to be decanted off, and pro- 

 terved in a well (topped bottle. This liquor, when fresh prepared, dis- 

 covert lead by causing a dark-coloured precipitate. Domestic and 

 British wines, the nature of the fruit used in preparing them un 

 avoidably causing them to be more acid than those prepared from 

 UM (rape, are most likely to be impregnated with lead, particularly 

 as in some cookery book* it i* ignorantly recommended to sweeten 



Another important source of impregnation of articles of food with 

 lead is connected with the use of earthenware glazed with lead. Any- 

 thing containing vegetable acid*, if kept in *uch vessels, will act on the 

 lead, and may produce poisonous effect*. Even milk cannot be kept 

 with safety in leaden-glazed dishes. For all preserves, jellies, Ac., 

 Bristol-ware, which i* glawd with salt, should be employed. No- 

 thing Ota be more dangerous than to keep vinegar in leaden bottles, 

 or even in jars glazed with lead. The use of acetate or sugar o! 

 lead to clarify syrup* or honey, or to render brandy pale, is to be 

 voided. Rum, hollands, and geneva are occasionally adulterated with 

 lead, and cause extensive evil Colouring cheese with red lead is 

 equally hazardous. 



Nitrate of lead in solution In water 1 part of nitrate of lead to 10 

 part* of water, termed Ledoyen't disinfectant i* useful put into night 

 table*, at a destroyer of sulphuretted hydrogen and sulphuret ol 

 ammonium. But Hi* inferior to manganate of potash. [ DISINFECTANTS.. 



In amall medicinal doset acetate of lead, which is almost the only 

 salt (.ImhiMtered internally, produce* a direct action on the tr< 

 of UM stomach, combining with the albumen, and forming compounds 

 which are for the mnst part insoluble in water and acids, but occa- 

 sionally forming other compound, which are soluble by the addition 

 of a anell quantity of acetic, hydrochloric, or lactic acid. As these 

 add* csist in variable quantities and under different circumstances, the 

 degree and kind of action will be different, according as the lead is dis- 

 solved and conveyed to distant organs, or a* it remain* nearly utidis- 

 eolvedand accumulated on the mucous membrane. In the greater 

 number of ewe* it i* very slowly introduced into the circulation. Even 



a considerable dose may dinpUy merely local effect*, exciting irritation 

 and inflammation ; though these are sometimes followed by colic, 

 convulsions, coma, or local palsy, and amaurosis or deafness. 



By a repetition of small doses the secretion of most mucous surfaces 

 is diminished, and constipation occur* ; the heart's action U reduced, 

 and the calibre of the arteries is lessened and exhalation checked : if 

 Hemorrhage should exist, that generally stops. Acetate of lead thus 

 appears to bo decidedly sedative and astringent It manifests its 

 sedative effect even when applied externally, and lessens discharges 

 From ulcers, though its application to these is not always safe. Even 

 white-lead (carbonate of lead) ointment applied to ulcers has proved 

 fatal. 



Acetate of lead should always be dissolved in distilled, not in 

 common water. It ia a most improper application to inflamed cornea 

 whenever that is ulcerated, as it forms a white compound which is apt 

 to get imbedded in the cornea. 



The diseases in which it proves most useful ore increased discharge!, 

 either from mucous surfaces or in htcmorrhages. Vinegar should 

 always be given at the same time. In diarrhoea, dysentery, but, above 

 all, in cholera, when combined with opium, it is a most efficacious 

 remely (Dr. Graves, in 'Medical Gazette/ Oct. 14,1887); in fevers 

 attended with diarrhoea it is also useful. Combined with opium on 

 which boiling water has been poured, it forms a most grateful wash to 

 erysipelatous and other inflamed surfaces. In all cases care must be 

 observed in its use. In poisoning by acetate of lead or by litharge, 

 the best antidotes are sulphate of sodji (Glauber salts), sulphate of 

 magnesia (Epsom salts), or alum, to decompose or form an insoluble 

 compound, and afterwards the stomach-pump may be used, or emetics 

 of sulphate of zinc may be given. [PAINTERS' COLIC.] 



The whole subject of the action of lead upon the human system has 

 been very fully treated by Dr. James Alderson, in his ' Lumleian 

 Lectures,' printed in the 2nd vol. of the ' Lancet,' for 1852, p. 72, 4c. 



LEAD MANUFACTURE. Lead (French, p tomb; Italian, plnmto; 

 Spanish, plomo ; Portuguese, chumbn (all from the Latin jiiumliiun); 

 German, Uci ; Dutch, l-xtl ; Russ., tirinrtz) was known and used by the 

 Greeks and Romans for various purposes ; among others, it was 

 employed for pipes to convey water, just as it is now. The lead-mine* 

 of Britain were worked by the Romans, of which we have evidence in 

 the pigs of lead preserved in the British Museum, and stamped with 

 the names of the emperors Domitian and Hadrian. The early writers 

 in this country, when speaking of the metals, are so confuted, that it is 

 by no means certain of which of them they are treating. This con- 

 fusion is BO great, that Sir George Harrison, when writing in exposition 

 of the stannary laws of England, says, "in a liberal construction, copper 

 is tin." The trainers and early expounders of those laws fell into some 

 strange mistakes regarding even the nature of particular metals : these 

 mistakes affected lead as well as other metals. 



The principal lead-mines in Great Britain are in Cornwall, Devonshire, 

 Somersetshire, Derbyshire, Durham, Lancashire, Cumberland, v 

 moreland, Shropshire, Flintshire, Denbighshire. Merionethshire, and 

 Montgomeryshire; in Scotland, at the Lead Hills on the borders of 

 Dumfriesshire and Lanarkshire, in Ayrshire, and in A rgyleshire. In 

 Ireland, lead is found in the counties of Armagh, Wexford, Wicklow, 

 Waterford, Clare, and Down. No certain account of the produce has 

 ever been obtained : the proprietors or occupiers of the principal 

 mines declining, from prudential motives, to give detailed statements 

 to that effect. In recent years, however, approximate estimates have 

 been mode, which we shall notice in a later paragraph. 



The ore of lead, when extracted from the mine, is called galena, and 

 is combined with various earthy matters. This galena, an impure sul- 

 phide or sulphuret. is the most important among the ores of lead ; it 

 contains 86 parts of lead to 1 -4 of sulphur. Uf other ores of lead, very 

 few are used as sources of the metal. The mining operations need 

 not be specially described here. [MIXING.] 



The first processes subsequent to its extraction are those of crushing 

 or pounding and washing the ore, in order to separate as far as possible 

 by mechanical means the impurities from the metal. The ore is then 

 smelted, sometimes in a common smelting- furnace and sometimes in a 

 reverberatory furnace, both of which are very similar in form and con- 

 >n to the furnaces used for melting and puddling iron. [IRON 

 MAXVFACTCIIK.] When the fusion has been continued long enough to 

 cause the expulsion of the sulphur contained in the ore, and the sepa- 

 ration of the earthy matter in the form of scoria, the latter, which 

 from its smaller specific gravity floats on the melted metal, is removed 

 from the furnace through an aperture provided for the purpose ; and 

 the lead U allowed to run into a largo iron pan, from which it is ladled 

 into cast-iron moulds. It then constitutes what is called piy-lcad. The 

 scoria still contains a portion of lead, and is subjected to the heat of 

 another furnace, called a slag-hearth, for it* separation, which occurs 

 upon its fusion ; the metal then falls into a cavity, whence it in run 

 and also cast into pigs. 



Before tracing th lead to its employment in manufactures, we must 

 notice a very rein irkable reward which ingenuity has reaped. The 

 pig-leul always contain loss of silver. The proportion is 



ixjiin'tiiiii'- e,\< 'e dingly minute, being not moro than one ounce per ton 

 in the metal raised in Derbyshire and Shropshire, while in every tun of 

 the lead from Devon and Cornwall there is found from 20 to 40 ounces 

 of ilver : in some instances very much more. The produce of other 



