CHAPTER 13 



Cleaning, Labeling, and Storing Slides 



There is not much point in going to all the trouble and difficulty of 

 making a good microscope slide unless one is also prepared to finish, label, 

 and store it properly. There is a great deal of difference between a slide 

 that is merely left after the coverslip has been placed on it with a label 

 stuck roughly on the end and one that has been properly finished and 

 properly labeled. This, indeed, is the principal difference between the 

 "professional" slide purchased from the biological supply house and 

 one that is turned out by the average beginning student. 



There are two stages to finishing a slide. The first of these is to clean 

 from the outside all unwanted mountant and to polish the glass. The 

 second is to attach to it a label that is both neat and permanent. It is 

 easy to remove the unwanted gum mountant from wholemounts if one is 

 using either the medium of Farrants or the medium of Berlese, for it is 

 necessary only to wipe very gently with a damp cloth until the surplus 

 has been removed. If far too much of the medium has been used, so that 

 there is a large exudate around the edge of the coverslip, it is usually 

 better to work in two stages; that is, to remove about half of this exudate 

 one day and the remainder the next day. The reason for this is that these 

 gums harden only on the outside and, if the whole of the surplus is 

 washed off at one time, there is a grave risk of displacing the coverslip. 

 A somewhat different procedure is employed when one is cleaning a slide 

 that has been mounted in the medium of Gray and Wess. This material 

 dries to a tough pellicle which is not water soluble but is easily removed 

 with a knife. The sharp point of a scalpel is run either around or along 

 the edge of the coverslip, and then the surplus hardened pellicle is picked 

 off as a single sheet. The cut must extend all the way through to the glass 

 or the coverslip, with the object attached to it, may come off. However, 

 this is not a permanent catastrophe because one can easily remount the 

 coverslip with its adherent object in the same medium. 



In either case, after the surplus medium has been removed, the slide is 

 left for at least two days to harden, dipped very briefly in a finger bowl 



168 



