BIOLOGY FOR YOUNG BEGINNERS. 



34i 



something like these in all the substances we are going to examine. 

 They are called cells. Sometimes cells are quite colorless and clear cr 

 transparent, but here you see they are colored some are green, some 

 red, and others are red in the middle and green at the border. You 

 will notice that this coloring is all inside the cell, and not in the wall 

 or outside, cover of the cell ; and sometimes, though not often, you can 

 see this coloring-matter is formed in little grains. Now I wisli you to 



Fig. 1. Mould- 

 Cell. 



Fig. 2. Green MorLD- 

 Cell. 



Fig. 3. Mould-Cell 

 with Red Centre. 



Fig. 4. Red Centre 

 and Green Border. 



notice the size and shape of the cells. You will find that most of 

 them are from -g^-^ to j-^Vo of an inch in size, and nearly all of them 

 have a round shape. Let us see now how many different things we can 

 find in these cells. First, there is the outside cover or sac ; this sac 

 seems to be filled with something that looks like jelly, or the white of 

 an egg, and in this jelly you can see the green and the red colored 

 grains, a little round, hard-looking body that looks like a kernel, and 

 sometimes in the middle of the sac there is a thin, empty-looking space. 

 We will begin at the outside and look at each of these things sepa- 

 rately, and try to find out what they are. If you press some of the 



Color- 

 grains. 

 Air-cell. 

 Cell-wall. 



Cell-wall. 



Jelly, or proto- 

 plasm. 



Fig. 5. 



Fig. 6. Broken Cell. 



cells lightly they will burst, the soft inside part will flow out and leave 

 the empty sac just the shape of the cell except where it is torn. This 

 shows that the outside is much stronger and tougher than the inside. 

 Chemists have found that this wall of the cell is made exactly the 

 same as the tough cells of wood it is called cellulose. 



The light-colored jelly inside the sac has a long name of its own 

 protoplasm which me&vs Jirst form or mould, because this seems to be 

 the first form of all life. The green and the red colored grains are 

 called chlorophyll. The word means green leaf. But chlorophyll is 

 not always green : as you see in this mould, it is sometimes red, and it 

 has many other colors ; nor is it found in leaves only, as you will see 

 when we come to study the stems and flowers of plants. But this dye- 

 stuff or coloring-matter was first found in the leaves, hence its name 



