CHAPTER V. 



PRODUCTS OF THE CELL. 



I. CHLOROPHYLL. 



63. In many plant-cells definite portions of the proto- 

 plasm have a green color, on account of the presence of a 

 peculiar chemical compound known as Chlorophyll.* The 

 protoplasmic bodies thus colored are called chlorophyll-bod- 

 ies, or chlorophyll granules, while to the coloring-matter 

 alone, distributed in small quantity through their substance, 

 the name chlorophyll is properly applied. 



64. The chlorophyll-bodies are of various shapes and 

 sizes. In some of the lower plants nearly the whole of the 

 protoplasm is colored, giving the whole cell a uniform green 

 color. In others there are stellate or band-like chlorophyll- 

 bodies distinct from the mass of the protoplasm of the cell ; 

 the band-like bodies are straight, or more commonly spiral 

 (Fig. 42). In the great majority of cases, however, the 

 chlorophyll-bodies are simple rounded granules of such mi- 

 nute size that many are contained in a single cell (Fig. 43). 

 The chlorophyll may be dissolved out of its protoplasmic 

 vehicles, leaving the latter with the appearance and chemi- 

 cal properties of ordinary protoplasm. 



65. The exact chemical composition of chlorophyll is not 

 known. As obtained by the evaporation of its alcoholic 

 solution it is a green resin-like powder, insoluble in water. 

 From the partial analyses of Kromayer it is probable that it 

 contains carbon, hydrogen, nitrogen, and oxygen, and there 

 are good reasons for believing that iron is also one of its con- 

 stituents. 



* Chlorophyll is also found to a limited extent in the animal king- 

 dom. It is present, for example, in Euglena and Hydra. 



