INTRODUCTION 



THERE are large numbers of people, who unfortunately miss a 

 great many of the good things of this world. They live their 

 lives without knowing anything of the wonders that surround 

 them. There are some keen searchers after knowledge, alive to 

 the fact that time is precious, and there is much to learn but 

 there are also countless numbers who are so ignorant that they 

 do not realise that there is anything beneath the surface, and 

 they simply live to make the best of their positions, and take 

 interest in nothing in particular. And there are yet a few 

 one meets such occasionally that scoff at everything which does 

 not concern them personally. 



The reader will, I hope, peruse this introduction carefully, as 

 it may add to his or her pleasure, for a little elementary know- 

 ledge is required if the intention is to take an intelligent interest 

 in what follows. 



Every living thing, whether plant or animal, whether it be 

 the leaves, flowers, or fruit of the former, or flesh and muscle of 

 the latter, is made of many single cells, and each cell essen- 

 tially consists of a wall that surrounds it, protoplasm, and a 

 nucleus. 



Protoplasm without nucleus cannot exist, nor can the 

 nucleus without protoplasm. And each cell is typically alive 

 that is to say, it is able to multiply, to make more of its kind. 

 Thus an animal grows larger year by year the ovule forms the 

 plant. 



Living things are roughly divided into (1) single-celled, (2) 

 many-celled things. The single- celled animals are known as 

 Protozoa many-celled as Metazoa. 



When a cell multiplies, the nucleus divides and its parts take 



