LETTERS TO BROTHER JOHN. 163 



symptoms will be produced by a disturbance in a 

 different living action. The same symptoms, there- 

 fore, frequently require different treatment; because 

 the cause of those symptoms is different, although 

 the symptoms themselves are the same. I will 

 give you a familiar instance. One man has a foul 

 tongue, a quick pulse, and a dry skin, produced by 

 inflammation of one of the membranes of his brain : 

 he therefore requires leeches to his head. Ano- 

 ther man has the same symptoms, from inflamma- 

 tion of the mucous membrane of the bowels : he 

 requires leeches too not to the head, but to the 

 abdomen.' Again, if a medical man finds his pa- 

 tient in pain, he does not forthwith run home for 

 a dose of opium, because opium has sometimes the 

 power of relieving pain ; but he first ascertains which 

 of the vital actions, which, being disturbed, is pro- 

 ducing that pain. If it arise from spasm, opium 

 may be of service ; but if it arise from inflammation, 

 opium will do harm, instead of good. If it were 

 only necessary to attend to symptoms, and not to 

 the cause of those symptoms, then the proper re- 

 medy for a foul tongue would be a scraper. One 

 man has headache from inflammation of the brain ; 

 another from flatulence of the stomach: brandy 

 will kill the one, and cure the other. 



