64 MATERIA MEDIC A AND THERAPEUTICS. 



ACTION AND USES. 

 1. IMMEDIATE LOCAL ACTION AND USES. 



Externally. In the form of the solid pencil, nitrate of 

 silver is a caustic causing destruction, with deep staining of 

 the superficial layers, acute pain, inflammation of the deeper 

 layers, separation of the part as a slough, and then rapid heal- 

 ing. Unlike potash, its effects are limited to the area of appli- 

 cation. On this account it is the best caustic for ordinary use, 

 to destroy the affected part in bites of dogs, serpents, and other 

 venomous animals, in post-mortem wounds and chancres, or to 

 remove small growths. Solutions of the nitrate, when applied 

 to the broken skin or a mucous membrane, exert much the 

 same action as lead, but in a greater degree : precipitating the 

 albumins and the chlorides of the plasma or secretions ; coagu- 

 lating the protoplasm of the young cells of the part ; causing 

 active contraction of the arteries, veins, and capillaries; and 

 very rapidly coagulating the blood both within and without 

 them. Nitrate of silver is therefore the best local antiphlo- 

 gistic known, controlling the exudation, growth, and vascular 

 disturbance of the inflammatory process. It is employed to 

 touch callous and weak ulcers, including bed-sores ; to control 

 local inflammations in accessible parts; and, as an injection, to 

 wash inflamed surfaces, for example, the urethra, vagina, os 

 uteri, bladder, and conjunctiva. A weak solution is used to 

 harden the skin in threatening bed-sores. Solid caustic is an 

 excellent haemostatic on bleeding from leech-bites. 



Internally. In the mouth, silver causes a nauseous astrin- 

 gent metallic taste. Meeting with chlorides and albuminous 

 fluids, it combines with these, and acts upon the surface of 

 the mucous membrane as it does upon the skin. It is a useful 

 remedy in inflammation of the tonsils and pharynx, whether 

 applied in the solid form as an antiphlogistic in acute 

 cases, or in solution as an astringent in relaxed, chronic 

 states. 



Reaching the stomach, nitrate of silver is decomposed by 

 the hydrochloric acid and mucus, and cannot act as an irritant 

 upon the mucous membrane unless given in poisonous doses. 

 Its use in ulcers of the stomach must therefore be ques- 

 tioned. When given for ulceration of the bowels, it is admini- 

 stered per rectum. 



2. ACTION IN THE BLOOD. 



Silver enters the blood either as albuminate, or is absorbed 

 as the pure metal by the intestinal epithelium and lacteals, 



