A CHAPTER FOR BOYS 373 



Presently we perceive that some are changing their 

 form. A moment ago, the first one we inspected was 

 as round as a watch crystal; now it has become ellip- 

 tical in form. A few minutes later, we look again, and 

 it has stretched itself out into a long filament like an 

 angleworm. Presently, it begins to draw itself up 

 into a round mass again; and in less time than is re- 

 quired to describe the action, it has assumed its original 

 shape, but has changed its position. That is the way 

 the little creature moves about. It makes itself into 

 the shape of a worm, and crawls just as a worm does, 

 by making one end fast, and drawing the rest of the 

 body up. 



But what does it move about for ? Why may it not 

 remain stationary! Shortly, we shall see, if we watch 

 carefully. Even now the reason is evident. Eeader, 

 just peep over our shoulder a moment. Put your eye 

 down to the eyepiece of our microscope. Do you see 

 the little fellow! Look sharp, and you will. A few 

 seconds ago it was round as a full moon. Now there 

 is a little pocket in one side. The pocket is growing 

 deeper and deeper. "VMiat is the object of such a curi- 

 ous procedure ! Let us put on another eyepiece. Now 

 we have magnified the object a million times. See 

 how much larger it looks. Now look at the pocket. 

 The mystery is solved. There is a little speck of food 

 which the little creature wishes to get, and so he has 

 made a pocket in which to put it. 



The queerest part is yet to come, so we must watch 

 patiently a moment more. Now the mouth of the pocket 

 is closing up. Evidently, the little fellow is afraid he 

 may lose the precious morsel, and so he is about to 

 shut the pocket to prevent its escape. Now the open- 

 ing is closed, and before we are aware of it the pocket 



