BIOLOGY FOR YOUNG BEGINNERS. 



347 



space or vacuole, no " eye-spot," no eyelashes or cilia, and when it is 

 quite fresh and new you cannot see any kernel or nucleus. You really 

 can see nothing but an odd-looking lump, with here and there some lit- 

 tle grains inside of it. If you give it a drop of weak vinegar or acetic 

 acid, the little grains will disappear, and you can see the kernel in the 

 centre (Figs. 18, 19). 



You can find this kernel much easier if you stain the cell with ma- 

 genta or weak iodine. Heat makes these atnceboe or blood- cells move 



Fig. IT. 



Kernel. """' 

 Sac. 



Foot. 



Figs. 18 and 19. Cells cleared with Vinegar, so as to 

 show the Nucleus. 



much quicker, and it is very interesting to watch them make their 

 way among the yellowish-red cells which lie in rows all around them. 

 Sometimes one of the amceba3 will clear a channel for itself right 

 through a thick group of the others. The first time I ever saw them 

 moving in this way, I could not help thinking of the canals in Venice, 

 where the gondoliers steer their gondolas close beside the houses, 

 turning the corners so skillfully as never to strike them. So these lit- 

 tle o-ondoliers of the blood went in and out, threading their way among 

 the reddish-yellow cells, whicli stood in rows on either side the narrow 

 channels (Fig. 20). There is one great difference, though: in Venice 



Fig. 90. The Am<eb.e pushing their Wat among the Red Cells. 



the gondolier has nothing to do but follow the canals that are made 

 for him, but the amoeba gondolier has to make his way as he goes. No 

 wonder you open your eyes ! It is enough to open any one's eyes to 

 think of the thousands of these odd creatures that go half creeping, 

 half walking through one's veins. You know people sometimes talk 

 about their " blood crawling," but very few people know how the blood 

 crawls. 



If you heat the amceba? they pull in all their little feet and become 

 perfectly white and still, and nothing you can do will ever bring 



