340 POISONS, CONTAGIONS, MIASMS. 



All substances administered as antidotes in cases 

 of poisoning, act by destroying the power which 

 arsenious acid and corrosive sublimate possess, of 

 entering into combination with animal matters, 

 and of thus acting as poisons. Unfortunately no 

 other body surpasses them in that power, and the 

 compounds which they form can only be broken 

 up by affinities so energetic, that their action is as 

 injurious as that of the above-named poisons them- 

 selves. The duty of the physician consists, there- 

 fore, in his causing those parts of the poison which 

 may be free and still uncombined, to enter into 

 combination with some other body, so as to pro- 

 duce a compound incapable of being decomposed 

 or digested in the same conditions. Hydrated 

 peroxide of iron is an invaluable substance for this 

 purpose. 



When the action of arsenious acid or corrosive 

 sublimate is confined to the surface of an organ, 

 those parts only are destroyed which enter into 

 combination with it ; an eschar is formed which is 

 gradually thrown off. 



Soluble salts of silver would be quite as deadly 

 a poison as corrosive sublimate, did not a cause 

 exist in the human body by which their action is 

 prevented, unless their quantity is very great. This 

 cause is the presence of common salt in all animal 

 liquids. Nitrate of silver, it is well known, com- 

 bines with animal substances, in the same manner 

 as corrosive sublimate, and the compounds formed 



