CHAPTER XXXII 



CONTENTS AND PRODUCTS OF CELLS 



394. THE LIVING CELL IS A LABORATORY. I n nearly all 

 cells are found one or more non- protoplasmic substances 

 which are produced bj the plant. Some of these are verj 

 useful to the plant, and others seem to be discarded or 

 excretory products. There is considerable division of labor 

 among the cells of higher plants, one cell or group of cells 

 producing one product and another cell producing another 

 product. 



395. 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 presence is absolutely uecessarj in all plants which have 

 to secure their nourishmenl whollj or in pari from the air 

 .mil from mineral matter <>f soil. Review Chapter XII. 

 Mosl parasites aud saprophytes do do! bear chlorophyll, 

 Imt live <>ii organic matter (Chapter XIII). The oval 

 bodies in the eel) of Pigs. 111. H3, Ml. are chlorophyll 

 bodies. 



396. cellsap. Often the mosl abundant of the differ- 

 en! cell-contents is cell-sap. It maj contain a number of 

 differenl substances, manj of which are in solution and can 

 be detected bj the use of chemical reagents. Some of tl 

 subs! ances are : 



milk ( lactose I . 



i/iii/n ( glu ' or dexl rose,< II 



Sugar, fruit (levulosi 



cam ( sacchar< ise, C II On) . 



///</// ( malt* >so ) . 



