212 LETTERS TO BROTHER JOHN. 



quantity, I have only to direct your attention to a 

 foul tongue. Look at the tongue of a sick man : 

 instead of being bathed in the natural, pellucid, and 

 fluid secretion of the mouth (saliva), it is covered 

 with a thick, and filthy, and pasty fur, which is 

 actually solid. Is it possible to conceive that the 

 offices intended to be fulfilled by the saliva can be 

 properly effected, or effected at all, by the nasty, 

 pasty filth which you behold in this mouth, instead 

 of saliva 9 This filth is secreted from the blood ; 

 and poured into the mouth by those arteries which 

 ought to secrete only that thin, clear, pellucid 

 fluid, called saliva. Now this is an example of 

 vitiated secretion which you can actually see, and 

 which cannot, therefore, be doubted or questioned. 

 Can you have any difficulty in believing that the 

 other secretions of the body, which are all formed 

 from the blood, may, in like manner, be equally 

 altered and vitiated? Can you, moreover, have 

 any difficulty in believing that the body must, of 

 necessity, be badly nourished in this state of the 

 secretions, seeing that it is by the agency of these 

 very secretions that our food is converted into 

 blood, which blood is the sole source from which 

 our bodies derive nutrition and support ? 



