LETTERS TO BROTHER JOHN. 67 



arranged as to form also its most delicate mem- 

 branes. 



A knowledge of the nature and structure of 

 membranes is of the highest possible importance in 

 all that regards the regulation of our diet ; for the 

 stomach and bowels are lined with one of those 

 most delicate, and therefore extremely irritable 

 and highly sensible, and easily-offended membranes, 

 called the " mucous membrane of the stomach and 

 bowels." It is with this membrane that all which 

 we eat, and all that we drink, comes directly in 

 contact. Here, then, is another powerful reason 

 for caution in what we eat and drink. This mem- 

 brane is no thicker than gold-leaf; and you know 

 very well that you can scarcely touch a leaf of gold 

 without injuring it without deranging, and even 

 tearing it. Remember, when you are eating your 

 dinner, that the membrane, on which every mouth- 

 ful falls, is no thicker than a leaf of gold. 



In contemplating any part of the body knowing, 

 as you now do, that it consists of arteries, veins, 

 nerves, and absorbents you will please always to 

 bear in mind what are the offices or functions which 

 these structures severally fulfil. You will recollect, 

 that it is the function of the lymphatic absorbents 

 to eat away the body; that of the arteries (or 



