RED OXIDE OF LEAD.

655

assuming' that the oxide of lead unites with carbonic acid in the lungs, and isthus converted into carbonate: and that the acetate, citrate, and tartrate, are de-composed in the alimentary canal, and converted into carbonates. But it appearsto me to be much more simple and eonsistent with analogy, to admit that thesepreparations are of themselves capable of producing colic, than to assume thatthey undergo the changes here supposed. Moreover, in some instances in whichcolic was produced, it is unlikely that these changes would have occurred, owingto the excess of acid taken with the Salt of lead.

Tj gEg __ rp ne uses 0 f the preparations of lead may be in part inferred from the

foregoing account of their effects. These agents are employed when we wish toconstrino-e the capillary vessels and to diminish their vital activity. Thus we ad-mimster^them internally to check excessive secretion and exhalation, as in catarrhalaffections of the mucous membranes of a chronic nature; in profuse secretion ofpus; in sanguineous exhalations from the mucous membranes; and colhquativesweäting. They have also been applied, in some instances with success, in cer-tain chronic affections of the nervous System, as epilepsy; but the practice is alto-gether empirical, as we have no rational principles, to guide us in using them. Astopical remedies, 1 we employ the preparations of lead to diminish vascular excite-ment, to allay pretematural heat, and to check excessive secretion. Thus we ap-ply them to inflamed parts to promote resolution, and to ulcers and other secretingsurfaces as astringents or desiccants. During the internal employment of lead, at-tention must be paid to the condition of the gums, stomach and bowels, as we findtraces of their injurious effects in these Organs. The blue line on the gums hasbeen noticed. Constipation is a very frequent result of the medicinal employmentof lead. Loss of appetite, indigestion, and griping pains, are also often noticed.The tendency to colic is diminished, according to Dr. A. T. Thomson, by con-joining acetic acid.

Antidotes.— Poisoning by lead usually puts on one of three forms— irritantpoisoning, lead colic, and paralysis; and the treatment varies with cach.

In irritant poisoning administer diluents holding in Solution some sulphate (assulphate of soda, of magnesia, or of potash or alum,) so that a sulphate of lead maybe formed. If vomiting have not already come on, tickle the throat, and administeremetics of the sulphate of zinc or of copper, or the stomach-pump may be em-

In lead colic the best remedy is alum (vide pp. 518 and 519.) But in thiscountry lead colic is frequently treated by the combined use of purgatives and ano-dynes, the purgatives being either castor oil or salts and senna, and the anodynebeing'opium. When the vomiting is very troublesome, and liquid medicines donot remain on the stomach, we may give the Compound extract of colocynth, withopium in the form of pill. In several cases in which the pulse was füll and strong,the face flushed, and the tongue furred and dry, I have used blood-letting withevident advantage. The sulphates have been recommended, as also mercury.

In lead paralysis, mix vomica, and its active principles—strychnia and bruciaare perhaps of ali internal remedies most deserving of trial, because of their specificeffect on the spinal marrow; and the chance of their success is, of course, muchincreased by the circumstance of there being no discoverable lesion of this portionof the nervous System. Mercury has been recommended by Dr. Clutterbuck.Various local measures have been tried, but without much benefit; for example,electricity and irritants (such as ammonia and cantharides.)

2. PLUM'BI OX'YDUM.—OXIDE OF LEAD.

(Litliargyrum, E— Plumbi O.xydurn semivitreum, 7J.)-(U. S')

History.— Theancients were acquainted with oxide (Protoxide) of lead. Hippo-

i See Dr Aikin's Ohscrvaüons on the Ezternal Use of Preparations of Lead. Lond. 177.

a In all cases tlie U. S. P, uses the i inetead Ol' y in spelling the latitl word for oxide, Ihus Ozidian,