CHAPTER XXXVII 



CONTENTS AND PRODUCTS OF CELLS 



449. The Living Cell is a Laboratory. — In nearly all 

 cells are found one or more non-protoplasmic substances 

 produced by the plant. Some of these are very useful to 

 the plant, and others seem to be waste or by-products. There 

 is considerable division of labor among the cells of higher 

 plants, one cell or group of cells producing one product, and 

 another group of cells producing another product and func- 

 tioning in a different way. We know that there is also 

 division of labor among the different organs of a plant. 



450. Chlorophyll. — Cells may contain chlorophyll bodies 

 if they are exposed to the sunlight. Chlorophyll is a green 

 substance infiltrated in a protoplasmic ground-mass. It 

 imparts color to all the green parts of the plant. Its pres- 

 ence is absolutely necessary in all plants that secure their 

 nourishment wholly or in part from the air and from mineral 

 matter of soil. Review Chapter XIV. Most parasites and 

 saprophytes do not bear chlorophyll, but live on organic 

 matter (Chapter XV). The oval bodies in the cell of Figs. 

 468, 470, 471, are chloroplasts. 



451. The Cell Contents. — The products formed in plants 

 are of varied character and exceedingly large in number. 

 Of the more common and most abundant products are the 

 following: 



Grape (glucose or dextrose, with the chem- 

 ical formula C 6 Hi 2 6 ). 

 Sugars \ Fruit (fructose or levulose CeH^Oe). 



Cane (saccharose C12H22O11). 

 Malt (Maltose C^H^Ou). 

 (270) 



