32 



BOYS AND GIRLS IN BIOLOGY. 



seen the rivers of China and India. I think now you 

 are anxious to know about your protococcus, or first 

 berry, what I wanted to know about the mould in the 

 old trough. What makes it look green ? You are 

 wondering w T hy it is not white, like the torul^e. This 

 color comes from little grains, in the jelly, or proto- 

 plasm, called chlorophyl. They are always found in 

 plants which grow in the sunlight. The word chloro- 

 phyl means green leaf. But the chlorophyl of plants 

 is not always green, as you see in the protococcus- 

 mould — it is sometimes red, and is found in the stem as 

 well as in the leaf. But it was first discovered in the 

 leaf, hence its name, green leaf which is so very easy, 

 it well help you to remember the long Greek name — 

 chlorophyl. All the plants which contain these color- 

 grains are called green plants. You remember, the 

 colorless plants are called fungi. It is found that green 

 plants must have the sunlight, whereas fungi, such as 

 toadstools, grow in the dark. But what is the good of 

 this dye-stuff, or chlorophyl ; is it of any use, or is it 

 there just to make the plant look pretty ? It is of great 

 use. Each grain is a very clever little chemist that 

 works in the cell, which is his workshop, or labora- 

 tory, and the sunlight is the fire by which he heats his 

 crucible, or melting-pot. Into this crucible he puts the 

 poison-gas, carbonic acid, that he gets from the air, and 



