CHAPTER II. 



THE MICROSCOPICAL AND CHEMICAL COMPOSITION OF 

 THE BODY. 



What the tissues are like. Having gained some idea 

 of how the larger parts of the body are arranged we may 

 next inquire what the tissues, its smallest parts which are 

 combined to make the larger, are like. 

 The simplest tissues are known as cells ; * 

 they are so small that a separated cell can 

 only be seen with the help of a microscope. 

 In a fully formed cell (Fig. 5) we find three 

 parts : (1) a cell body made up of a soft 

 granular substance ; (2) a smaller and less 

 granular cell nucleus imbedded in the cell 

 body ; and (3) a tiny dot, the nucleolus, 

 lying in the nucleus. Cells vary much in 

 form and size, though all are very small. A 

 good many, like those represented at ~b, 

 float in our blood, and are more or less 

 rounded. In other places cells are flattened to form thin 

 scales as those in Fig. 6, which represents cells scraped 



Of what are the larger parts of the body made up ? What are 

 the simplest tissues? What instrument must we employ in order to 

 see them ? Describe the structure of a cell. Describe some differ- 

 ent forms Of cells. 



* So called from an old belief that they were little bags or chambers. Most 

 cells are really solid or semi-solid throughout. 



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