LETTERS TO BROTHER JOHN. 65 



that I might add absorbents also ; although these 

 last have not yet, I believe, been discovered. 



I have now given you an account of the general 

 structure of the body sufficiently brief and rough, 

 but nevertheless sufficiently accurate and minute, to 

 enable you to understand the nature of the seve- 

 ral functions performed by the several organs of 

 nutrition, whenever I have occasion to speak of 

 these functions and these organs. This general 

 structure is so simple, that you can never forget it. 

 You have only to remember, that whenever you are 

 considering and presenting to your mind's eye any 

 part of the body whether it be the stomach, the 

 liver, the heart, the bowels, or the arteries and 

 veins whether it be the solid bones, a mass of flesh 

 an inch thick, or a delicate filmy membrane no 

 thicker than the gilding of your picture-frames it 

 is still the same; it is still nothing more than 

 a matted congeries of arteries, veins, nerves, and 

 absorbents, held together by, and wrapped up 

 in, the meshes of the cellular web. Cellular web is 

 a better term than cellular substance: for, when 

 spread out, it has a good deal the appearance of a 

 spider's web^ and has, moreover, of real substance, 

 extremely little indeed. 



Take four threads of different colours a scarlet 



