IV 



,1 .r 'APPLIED PHYSIOLOGY 



An animal that can make any part of its body anew to 

 suit itself should be very prosperous and happy. In fact, 

 the ameba does grow so fast that in a day or two it thinks 

 itself big enough to become two animals, and so it splits 

 itself into two parts, and each half goes off by itself as a 

 full-grown ameba. 



2. Cells. Man has a separate part of the body set 

 aside to do each kind of work. He has legs which carry 

 him to his food, and arms with which to get the food, and 

 a mouth with which to eat it. But these parts do not 



make the real man, for 

 some men lose their arms 

 and legs and yet remain 

 men. The real man is the 

 mind which lives in the 

 body and makes the arms, 

 and legs, and mouth do as 

 it wants them to do. But 

 a man's arm or his leg, or 

 any other part of his body, 

 is itself made of millions 

 of little living things like 

 the ameba. We call each 

 of these living things a cell. Some of these cells are 

 long, some flat, and some of other shapes. Each has 

 the form best fitted for the work it does, but all are ex- 

 ceedingly small. They are held in place by fine strings 

 called connective tissue. By scraping the skin, cells can 

 be removed from its surface. They look like flour. 



3. Mind rules the cells. The mind takes good care 

 of these cells. When we eat we feed the cells, and we 

 breathe so that each cell can get a little air. To repay the 

 mind for its care the cells all work together like good ser- 



Cells from the human body (X 200). 



a A colored cell from the eye. 



b A white blood cell. 



c A connective tissue cell. 



d A cell from the lining of the mouth. 



e Liver cells. 



/ A muscle cell from the intestine. 



