i'^T. 93 



not absorbed ; and, secondly, from the portion excreted by the 

 liver (in the bile), and by the pancreas and intestinal glands. 

 It will thus be seen that but little use is made of the remote 

 local action of mercury. 



6. ACTION AND USES OF THE DIFFERENT PREPARATIONS OF 

 MERCURY. 



The preparations of mercury, although so numerous, can 

 be readily remembered, and their special actions understood, 

 when they are classified as follows : 



1. Metallic Mercury and preparations containing it. 



2. The Perchloride of Mercury and its preparations. 



3. The Subchloride of Mercury and its preparations. 



4. The Oxides, Iodides, the Ammoniated Mercury, and their 

 preparations, a complex group, the action and uses of which 

 closely correspond either with those of the perchloride or with 

 those of the subchloride. 



5. Acid Nitrate of Mercury and the Ointment corresponding. 

 1. Metallic Mercury and its preparations. These may 



be employed in all the classes of cases for which mercurials are 

 adapted. The metal itself is never given internally, except in 

 the finely-divided form in which it exists in Pilula Hydrargyri 

 and Hydrargyrum cum Greta. The blue pill is chiefly used 

 as a purgative and indirect cholagogue, but is also given in sy- 

 philis, in small doses combined with opium and quinine, and in 

 combination with digitalis and scilla as a diuretic (the famous 

 " Guy's pill)." Hydrargyrum cum Cret&, or " grey powder," 

 is a favourite purgative for children, and also a convenient pre- 

 paration for a course of mercury in syphilis. Unguent \\ m 

 Hydrargyri, or " blue ointment," is the usual means of admini- 

 stering the metal by inunction in syphilis. A portion as large 

 as a pea or hazel nut is rubbed daily into a soft part of the skin, 

 such as the inside of the thigh, or smeared on flannel, and ap- 

 plied round the loins, the gums being carefully wati-hrd. 

 This is a very sure and tolerably safe, but very dirty method, 

 which is chiefly employed with infants. The non-officinal oleate,!^ 

 painted on, is a great improvement in this respect. Mercurial 

 ointment may also be smeared over inflamed parts, such as tho 

 testis, and is used as a parasiticide. The Liniment of ML-ivury 

 (the ointment in a liquid form) is chiefly employed as an anti- 

 phlogistic, being soaked on lint and applied to the attWtrd 

 l>;irt, e.g. the joints or the abdomen in subacute peritonitis, 

 The same use may be made of the plasters, and of the compound 

 ointment, " Scott's dressing." The suppository may be used in 

 syphilis or to kill ascarides. 



