CHAPTER IV. 



THE HUMAN AND THE POND AMCEBiE. 



What Wonders the Boys and Girls found in a Drop of Blood, and 

 the Scum of Green Water; and how Blue-beard lost his Chance 

 of becoming a Scientific Man. 



Of course, you all know the story of Blue-beard ; 

 how he found out that poor Fatima had been to the 

 closet where he murdered his wives, because the key 

 was all stained with blood. Young folks have a strange 

 fancy for "bloody stories," and they are mostly always 

 afraid of blood, and so are a great many grown-up peo- 

 ple. Now I am going to tell you not exactly a " bloody 

 story," but a story about blood, and you need not be 

 alarmed, for, before I finish, you will find there is noth- 

 ing in blood to alarm any one, but a great deal that is 

 useful, curious, and beautiful. Boys are always cutting 

 their fingers or getting bloody noses, but you need not 

 wait for such an occasion, nor need you turn Blue- 

 beards in order to find some blood for examination. 

 If you prick your finger ever so little with a needle and 



