8 STUDY OF COMMON PLANTS. 



action of Schulze's solution. The blue color that pres- 

 ently appears indicates cellulose. 



VII. Examine similar sections of a coffee seed prepared 

 and mounted in the same way. Notice how the cell walls 

 differ from those of the date seed. 



VIII. Remove the testa of a castor oil seed, and cut 

 a few thin sections from the endosperm. Mount in pure 

 glycerine, and examine with the high power. 



1. The sections show (best on the edges where they are 



very thin) the cells of the endosperm filled with 

 numerous rounded bodies. These are aleurone 

 grains. They are of frequent occurrence in oily 

 seeds, and constitute an important food substance. 



2. Draw a cell with its contents. Examine the aleurone 



grains closely, and see if you can detect any struct- 

 ure. The small rounded body most frequently 

 seen at one end of the aleurone grain is called a 

 globoid. 



3. Run a drop of water under the cover glass and watch 



the effect. Some of the aleurone grains presently 

 show, besides the rounded globoid, an angular 

 crystalloid. 



Draw again a cell with its contents so as to show the 

 changes that have taken place. 



4. After the water has had sufficient time to act on the 



cell contents, it is evident that they are becoming 

 disorganized, and drops of oil are seen to have 

 passed out of the section. 



NOTE. It is important that all of these features should be sat- 

 isfactorily made out before proceeding farther. It may be neces- 

 sary to prepare a considerable number of slides, and possibly will 

 require several hours. The essential fact is that in the castor oil 

 seed two sorts of food are stored : one non-nitrogenous, in the 



