69 THE STUDY o/-' I.IVIXG CELLS. 



then with the higher (1-6 in.), using the C eye-piece and draw-tube 

 when necessary. 



OBSERVE: 1. The outline of the sections of the anthers; 

 oblong or quadrate, usually with rounded angles. 



2. The cavities near the angles ; later, these coalesce in pairs, 

 thus forming the two "anther-cells," or pollen-cavities. 



3. The epidermal layer of cells, the layer just beneath, and 

 the irregularly placed cells of the interior of the anther. 



4. Isolated rounded cells in the cavities or floating free in the 

 water. These are the mother-cells of the pollens. 



(a) The very thin cell wall, its smooth surface, etc., has it 

 perceptible thickness ? 



(b) The protoplasm of the interior, its characteristics. 



(c) The nucleiis, its appearance. 



(d) The nucleoliis. 



FURTHER PREPARATION : If (c) and (d) are not clearly demon- 

 straied apply a drop of iodine solution to one side of the cover- 

 glass, and place a piece of filter paper on the opposite side. This 

 absorbs the iodine and water, while the former acts on the proto- 

 plasm as a staining agent. (The iodine may be removed by using 

 water in the same way). 



Observe the relative amount of color given to the cell wall and 

 the cell contents; especially the effect on the nucleus after the 

 mother-cells have remained some time in the stain. Also observe 

 the increased distinctness of parts. From this study determine the 

 constant effects of iodine on protoplasm and refer to page 7 for 

 the use of this reagent in plant histology. 



Measure the diameter of the mother-cells by the use of the 

 camera lucida, or ocular micrometer, selecting those of extreme and 

 also of average breadth. 



If practical retain this slide in a moist condition until the next 

 preparation has been examined. It is useless to keep slides of soft 

 tissue containing protoplasm more than a few hours when mounted 

 in water. A temporary moist chamber can be made by placing a 

 small plate partly filled with water on a level surface and covering 

 it with a bell jar. The mount may be laid across a small watch 

 glass inside. Sketch transection of anther from objective and a 

 mother-cell from 1-6 objective. (Fig. 8). 



