46 PLAIN FACTS FOK OLD AND YOUNG 



looking closely you will see that it is made up of a 

 clear fluid in which are floating countless numbers of 

 little round bodies, called blood corpuscles. 



dueer Things in the Blood. —By far the larger 

 number of the blood corpuscles are flat, or disk-shaped 

 bodies, thinner in the middle than at the edge. They 

 are so small that thirty-five hundred of them arranged 

 in a row would extend only an inch. The separate 

 corpuscles are yellow or amber colored; but when 

 crowded together in great numbers, as they are found 

 in the blood, the mass appears red, from which fact 

 they are called red blood corpuscles. By looking very 

 sharp, if the microscope is a good one, you will see 

 here and there a corpuscle somewhat larger than the 

 rest, and of a white or grayish color. This is called 

 a white blood corpuscle. One of these is found to every 

 six or seven hundred of the red. 



The blood corpuscles are not inert bodies which 

 float in the blood current, but are living creatures. 

 Each one leads as independent and individual a life as 

 the fishes that swim in the water, or the birds that fly 

 in the air. 



The life of a corpuscle is supposed to continue 

 about six weeks. Several thousand die every second of 

 our lives, their dead bodies being destroyed and re- 

 moved from the blood by organs appointed for the 

 purpose. 



Traveling Tinkers.— Both kinds of corpuscles do 

 very important work. The white corpuscles travel 

 from point to point in the body, repairing diseased or 

 injured parts. They are like traveling tinkers, who 

 go about looking for umbrellas and tin pans to mend. 

 The red blood corpuscles are devoted to the business 

 of carrying oxygen, which they find in the lungs, and 



