Accurately mounted, labeled, and ringed slides should be filed away for future study and reference. Such filing may be done in slide boxes, in slide trays, or in cabinets. Slide boxes are to be had of a holding capacity varying from one to one hundred slides. For general use, slide boxes (Fig. 52) holding one hundred slides will be found most useful. Some workers prefer trays (Fig. 53), because of the saving of time in selecting specimens. Trays hold twenty slides arranged in two rows. The cover of the tray is divided into two sections so that, if desired, only one row of slides is uncovered at a time. Slide cabinets (Fig. 54) are particularly desirable for storing large individual collections, particularly when the slides are used frequently for reference. Large selections of slides should be numbered and card indexed in order to facilitate finding.
Fig. 54.—Slide Cabinet
Part II
TISSUES CELLS, AND CELL CONTENTS
CHAPTER I
THE CELL
The cell is the unit of structure of all plants. In fact the cell is the plant in many of the lower forms—so called unicellular plants. All plants, then, consist of one or more cells.
While cells vary greatly in size, form, color, contents, and function, still in certain respects their structure is identical.
TYPICAL CELL
The typical vegetable cell is composed of a living portion or protoplast and an external covering, or wall. The protoplast includes everything within the wall. It is made up of a number of parts, each part performing certain functions yet harmonizing with the work of the cell as a whole. The protoplast (protoplasm) is a viscid substance resembling the white of an egg. The protoplast, when unstained and unmagnified, appears structureless, but when stained with dyes and magnified, it is found to be highly organized. The two most striking parts of the protoplast are the cytoplasm and the nucleus. The part of the protoplast lining the innermost part of the wall is the ectoplast, which is less granular and slightly denser than most of the cytoplasm. The cytoplasm is decidedly granular in structure.