Part II.

-Materia Medica.

63

put them into a retort, and distil it first with a gentleheat, and afterwards with so strong a heat as to reddenthe bottom of the retort. In this process the nitric acidis partly decomposed, and passes over into the receiver inthe state of nitrous acid. The arsenioiis acid is at thesame time converted into arsenic acid, and combineswith the potass. The product, which isarseniate of po-tass, is found in the bottom of the retort, and may be ob-tained in the form of crystals, of a prismatic figure, bydissolving it in distilled water, filtering the solutionthrough paper, evaporating, and crystallizing. A prepa-ration of M. Macquer's.

4. Arsenious acid, in substance, to the extent of an eighthof a grain for a dose, combined with a little sublimed sul-phur, has been said to be exhibited in some very obsti-nate cases of cutaneous diseases, and with the best ef-fect.

.'. Combined with six times its weight of black pepper, itis given by the native physicians in the East Indies forthe cure of the Persian fire (syphilis), and a species ofelephantiasis, called juzam.

The internal use of arsenic has been lately much extended,in consequence of the observations of Dr Fowler, Mr Jenkin-son, Dr Bardsley, Dr Kellie, Mr Hill, &c. Before Dr Fowlerwrote, it was indeed in use empirically, for the cure of can-cers, and even as a popular remedy, in various countries ; asin the East Indies, against cutaneous affections; and in thefens of Hungary and Lincolnshire, against the ague. But DrFowler first, by that inductive method of ascertaining its ef-fects which he so successfully practised, recommended it tothe notice of regular practitioners. He confined him self tothe advantages derived from it in periodical diseases; and MrJenkinson has, more recently, extended the use of it to cer-tain painful affections of the bones, cases of" very long stand-" ing, attended with great debility, and local affections, not" of the muscles and integuments, but of the ends of the bones," cartilages, or ligaments, or of all three together." He thinksit hurtful in recent affections, except where there are regularintermissions, and in the disease described by Dr Haygarth,under the title of nodosity of the joints. For a complete listof the diseases in which it has been tried, Mr Hill's paper inthe Edinburgh Medical Journal may be consulted.

The great difficult}' attending the exhibition of so very ac-tive a remedy, is regulating the dose so as to produce the fulleffect, without carrying it farther than is absolutely necessary.