THE HUMAN AND THE POND AM(EBiE. 69 



deal more yet to be learned, so you must all try 

 to see what you can find out about them by your 

 own experiments. The red blood-cells are consid- 

 ered of more importance than the white, because 

 they make the blood good and rich ; but we cannot 

 study about them just now. If you make the amcebje 

 hot, they pull in all their little feet and become per- 

 fectly white and still ; nothing you can do will ever 

 bring them back to life. The cells I have described are 

 called human amoebae, or amceba of man. Those that 

 are found in the blood of other animals are somewhat 

 different; but there is a kind of amceba, or crawling 



Fig. 65. 



Fig. 66. 



Q 



Pond Amceba. Pond Amceba. 



jelly, which grows in stagnant water, that has a greater 

 difference. Take a little of the scum that rises on 

 ponds in hot weather and put it under the microscope, 

 and you will find amoebae of a much larger size, from 

 tto to two °^ an ^ nc ^ L ^ n diameter (Fig. 65), moving 

 about by the same kind of queer-looking feet (Fig. 66). 

 But the edge, or border, does not look at all the same. 



