456 MATERIA MEDIC A 



those parts to wliicli tliey are applied : sucli are the pure alkalies, 

 potash, and soda ; the sulphuric and nitro^is acids, or a solution of 

 silver, quicksilver, or copper, in nitrous acid. If a solid caustic is 

 Avanted, nothing is more convenient than the lunar caustic {nitrate 

 of silver). Tiie milder cavistics are more frequently useful than 

 those we have mentioned; such as blue vitriol {sulphate of copper), 

 red precipitate {nitric oxide of mercury), burnt alum, verdi- 

 gris, &c. 



The strong caustics are employed to destroy unhealthy or dis- 

 eased parts, such as warts and other excrescences, cleansing foul 

 ulcers and sinuses, so as to bring them to a healthy state, and 

 cui-al)le by more simple applications. Caustics may be divided 

 into liquid and solid, strong and mild. The mild caustics ai*e 

 also called escharotics, and are more useful than the stronger 

 caustics, which are too violent in their action, in many cases, and 

 often require to be diluted with water, spirit, or unctuous sub- 

 stances, according to the nature of the case. 



SOLID CAUSTICS, STRONG. 



No. 1. The red hot iron. See Firing. 



No. 2. Pure potash with lime. 



No. 3. Nitrate of silver, or lunar caustic. 



No. 4. Nitrate of copper. 



MILD CAUSTICS, SOLID. 



No. 1. Acetate of copper, or distilled verdigris. 



No. 2. Sulphate of copper or blue vitriol. 



No. 3. Red nitrated quicksilver, red precipitate, or nitric 



oxide of mercury. 

 No. 4. Burnt alum. 

 No. 5. Common verdigris. 



Bemark. — The strong caustics are generally sold in a con- 

 venient form for application ; but the mild require to be finely 

 powdei'ed and sprinkled on the ulcer : they are sometimes mixed 

 with digestive ointments to increase their power. 



STRONG CAUSTICS, LIQUID. 



No. 1. The sulphuric and nitrous acids, which ai'e very power- 

 ful, and must be used cautiously: they may be diluted 

 with diiferent proportions of water, so as to be ap- 

 plicable to many purposes. 



No. 2. Nitrous acid 1 oz. 



Quicksilver ^ oz.* 



* Red precipitate or nitric oxide of mercury may be substituted for quick- 

 silver. 



