

FURNITURE, AND ITS USES. 205 



they contain more or less of substances which 

 not only do no good, but are positively hurtful. 

 Even water can hardly be said to make either 

 chyle or blood ; but then it quenches our 

 thirst, and answers many important and even 

 indispensable purposes. 



I am now to tell you about the blood ; 

 first, what it is ; secondly, its uses ; thirdly, 

 how it is kept in a good and healthy condition. 



NATURE or THE BLOOD. If we open a 

 vein with a lancet as you know physicians 

 sometimes do and draw out a quantity of 

 blood into a bowl, or any other vessel, and let 

 it stand in the open air, it soon begins to clot 

 or thicken, or, as it is usually called, coagulate. 



From the surface of this coagulated part, a 

 yellowish watery fluid oozes out, in numerous 

 small drops, which gradually increase and unite, 



Itill, in a short time, there is more of this thin 

 liquid than there is of the thicker coagulated 

 part. This watery part is called the serum. 



If we take the coagulated part of the blood, 

 and wash it thoroughly, though carefully, we 

 may divest it of nearly all its coloring matter, 

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