FURNITURE, AND ITS USES. 207 



fibrine, and the serum. The serum is princi- 

 pally albumen and water ; though it also con- 

 tains, in small proportion, besides sulphur and 

 iron, a great variety of substances, especially 

 salts. Albumen is a substance which you may 

 consider as resembling the white of an egg ; 

 for the latter is almost wholly composed of it. 



USES OF THF BLOOD. All parts of the 

 human body, whether solid or fluid, and what- 

 ever may be their appearance or structure, are 

 formed from the blood. I have told you how 

 this fluid is sent out by the heart to all parts of 

 the system, even to the bones. I have also 

 said a few words about the saliva, and the 

 gastric juice, and the bile, and have called 

 them secretions. 



It may be necessary to observe, in this place, 

 that by the word secretion, as used in this 

 book, is meant something formed from the 

 blood. Not only the saliva, the tears, the gas- 

 tric juice, the pancreatic fluid, and the bile are 

 secretions, but the mucus which is everywhere 

 found in the mucous membranes of the body, 

 the water in the brain, the lungs, &c. In 

 short, wherever you find water or anything 



