APPLIED PHYSIOLOGY 



CHAPTER I 

 CELLS 



1. The ameba. In moist earth there lives a little ani- 

 mal called the ameba. It is so small that you cannot see 

 it without a magnifying glass many times as strong as the 

 best spectacles. When you do see it you will not know 

 that it is an animal, for it has neither eyes, nor head, nor 

 arms, nor legs. It is simply like a lump of jelly. But if 

 you look a minute, you will see it put forth some part of 

 its body like a finger to take a little lump of food. This 

 finger is also a mouth and swallows the food. Then the 



An ameba, sketched at intervals of ten seconds ( x 400) . 



finger becomes a stomach and changes the food to blood 

 so that the animal can grow. When it wants to go for a 

 walk, it puts forth a finger, and then the whole body rolls 

 itself into the finger, and thus it moves forward. So the 

 little ameba can make an arm, or a mouth, or a stomach, 

 or a leg, wherever and whenever it wants to. 



7 



