14 



BOYS AND GIRLS IN BIOLOGY. 



You can soon learn to use it, and it will give you more 

 pleasure than all the toys in old Santa Claus's pack, 

 with his sled and reindeers thrown in. You can never 

 get tired of it as you tire of toys, for it will always show 

 you something new. The first man who looked at yeast 

 through a microscope, saw these little bodies floating 

 about, but he did not know at all what they were ; he 

 thought they might be bits of barley. Sometimes they 

 are found quite alone (Figs. 1-3), but most frequently 



Fig. 1. Fig. 2. Fig. 3. 



O o CD O © 



Round Cells. Lemon-shaped Cells. Outer and Inner Sur- 



face of Sac. 



they are seen all joined together in groups, like boys 

 and girls at play (Figs. 4, 5). Each one is about one 



Fig. 5. 



Group of Cells. Group of Cells. 



three-thousandth of an inch in size, that is, if you 

 were to take a piece of an apple about an inch 



