THE AMEBA 5 



and self-supporting matter is an animal, although it 

 is so small that it can hardly be seen. Its body of 

 protoplasm with its more solid spherical nucleus, makes 

 up a single cell. 1 



The ameba, like all other animals consisting of but one 

 cell, has, in spite of its smallness and simplicity, the be- 



FIG. 3. Ameba progressing (side view). After photo-micrograph by Bellinger. 



ginnings of the faculties and powers which are so highly 

 developed in us. The possible exceptions are sight and 

 hearing, although it would seem not entirely to lack 

 even these, since experiments have shown that it is 

 influenced by light and even possibly by sound. Barring 

 accident, their lives may be said to be endless, since 

 each healthy adult undergoes division into young twin 

 cells of half the original size. These immediately take 

 on the characteristics and powers of the older cell, and 

 growing rapidly to maturity redivide in their turn. 



Reproduction by division. This process of division 

 begins and is completed in the nucleus before the sur- 

 rounding mass of protoplasm, the cytoplasm, changes. 

 The cytoplasm then proceeds to divide, and in a short 

 time the two new cells have entered upon an inde- 

 pendent life. This process is called reproduction by divi- 



1 Curiously enough, an independent cell somewhat like the ameba 

 is found in large numbers in the blood of the higher animals, and 

 is called a white blood corpuscle. The white blood corpuscles are 

 produced and set free within the body for the purpose of seeking 

 out and destroying any disease germs or other foreign substances 

 which have found a lurking place there. 



