170 



The Preparation of Microscope Slides 



Fig. 130. Slide-storage cabinet with vertical grooves. 



labeling. Slides should always be stored in the dark and in as cool a place 

 as possible because none of the stains used in biology is absolutely 

 permanent. Slides may be stored either vertically on edge in grooves in 

 a tray of a cabinet of the type shown in Fig. 130 or lying flat on the 

 bottom of a tray, as in the type of cabinet shown in Fig. 131. There are 

 arguments for and against both methods of storage. Slides that are stored 

 vertically occupy much less space than do those that are stored flat. The 

 former method is not very suitable for wholemounts for the reason that 

 the interior of the slide never dries and, after a slide has been stored for 

 some years in a vertical position, the object will be found to have dropped 

 down to the edge of the coverslip and become embedded in the hardened 

 balsam, from which it is very difficult to detach it later. There is, how- 



Fig. 131. Slide-storage cabinet for flat storage. 



