LARYNX, TUMORS OF. See TUMORS OF THE LARYNX AND LUNGS.
LEAD.—Leaci (plunabum) is not offi cial, as it is uot employed in medicine. Lead combines with oxygen forming ox ides, one of which (the yellow) is official (plumbi oxidum, U. S. P.), with the acids and with chlorine, iodine, bromine, etc., forming salts. Of these salts the acetate is the only one used internally to any extent, although the iodide is rarely used for alterative purposes. The acetate of lead (sugar of lead) occurs in efflorescent, colorless, shining transparent prisms, or flat crystals, having an acetous color and a sweet, metallic taste. It is soluble in 2 Va parts of cold, and in V, part of boiling water; in 21 parts of cold, and 1 part of boiling alcohol; in 3 parts of chloroform, and in 5 parts of glycerin.
Carbonate of lead (white lead, or ceruse) occurs in perfectly-white masses or powder. It is insoluble in water, but soluble in acetic acid and dilute nitric acid.
Iodide of lead occurs in a golden yellow powder and is insoluble in cold water, but soluble in 200 parts of boil ing water and in solution of the alkalies and of the iodide of potassium.
Nitrate of lead occurs in white crys tals, and is soluble in 2 parts of water.
Oxide of lead (litharge) occurs in a yellow to yellow-red powder and is in soluble in water, but soluble in acetic and nitric acids.
The above salts and their preparations are the only ones official in the United States Pharmacopoeia.
Preparations and Doses.—Plumbi ace tatis, 1 to 5 grains.
Phunbi iodidum, V, to 2 grains. Liquor plumbi subacetatis.
Ceratum plumbi subacetatis.
Liquor plumbi subacetatis dil.
Plumbi carbonas (used externally). Enguentum plumbi carbonatis. Enguentum plumbi iodidi.
Plumbi nitratis (used externally). Plumbi oxidum (used externally). Emplastrum plumbi.
Emplastrum resime.
Emplastrum saponis.
Ungnentum diachylon.
Physiological Action.—Unless a con centrated solution be used, lead applied locally acts as an astringent by inducing contraction of the capillaries. Hence its beneficial actions in inflammation. Con centrated solutions are irritating, on the contrary, and may induce inflammation.
Taken internally in therapeutic doses, lead also acts as an astringent, and di minishes the secretions of the gastro int,stnial tract. Beyond these effects the manifestations are those of poison ing. The nitrate. the subaeetate, mid the acetate are poisonous in the order named.
Acute Lead Poisoning.—Acute poison 111:- is rare, but may occur when a soluble salt (notably the acetate) is taken in poisonous amounts (not less than 1 ounce is necessary to produce serious effects). The symptoms are a sweet, metallic taste in the mouth, pain in the epigastrium, and vomiting of white milky-looking liquids, or white curds. mixed with food if z-.Iny food was present in the stomach. The white color indicates the presence of chloride of lead, formed by the action of the hydrochloric acid of the gastric juice. Later.. irritation of the intestinal tract occurs with an increase of pain, and either diarrhcca due to gastro-enteritis or. in some cases, obstinate constipation is noticed. The stools are generally black in color (from the action of the intestinal sulphuretted hydrogen-gas, which forms a sulphide). The pulse be comes rapid and tense. but later weak and compressible. The face is anxious and may be either pale or lived. Excess ive thirst is present, with cramps in the calves of the legs or muscular twitchings. In fatal cases coma, epileptic spasms, or collapse ensues. fp to the point of the affection of the nerve-centres (spasm, coma, or collapse) the prog,nosis is good; beyond this it is unfavorable.
Treatment of Acute Poisoning by Lead. —If there is reason to believe that any of the lead-salt is present in the stomach, the stomach-siphon may be used. Any soluble sulphate (Epsom or Glauber's salts) will decompose the lead salt and form an insoluble sulphate of lead; if used in excess the salts mentioned will act as purges and wash out the offending matter. Cramp and spasms may be re lieved by hot applications to the ab domen and to the extremities. Pain may be relieved by opiates.