CH. AY] 



SLIDES AND COVER-GLASSES 



247 



heat the slides over a Bunsen flame and remove the cover-glass. Place the 

 cover in cleaning mixture (§339). The slide may also be placed in cleaning 

 mixture or in some hot water containing 10% gold dust or other strong alka- 

 line cleaner. When the metal basin— preferably an agate ware basin— is two 

 thirds full of the slides, heat until the water comes to a boil. Then let it cool. 

 Add fresh water and most of the slides may be wiped clean. 



Fig. 190. Museum jar with clamp top 

 for storing cleaned slides and for preserving 

 specimens. [Cut loaned by the Whitall Ta- 

 tum Co.) 



If dichromate cleaning mixture is used the best method is to have a 

 museum jar of it and drop the slides in as they are rejected, or a large number 

 at once as is most convenient. It may require a week or more to clean the 

 slides with cleaning mixture. As this is a very corrosive mixture for metals 

 use only glass dishes in dipping into it. When the slides are freed from balsam 

 etc. pour off the cleaning mixture into another glass vessel and allow a stream 

 of water to flow over the slides until all the cleaning mixture has been washed 

 away. Then add distilled water and wipe the slides from that. An}' slides 

 still not freed from the balsam should be put back into the cleaning mixture. 

 Apparently the slides are not injured by a prolonged stay in the mixture. 



\ 332. Cleaning Slides for Special Uses. — In making blood films, for 

 micro-chemistry and whenever an even film is desired every particle of oily 

 substance must be removed. The slides should be placed in the dichromate 

 cleaning mixture (J 329) one day or more, thoroughly washed with clean 

 water and then in distilled water, or in 50% to 75% alcohol. The}' are taken 

 from the water or alcohol and wiped dry as needed. In wiping keep two or 

 more layers of the absorbent gauze over the fingers. Only one slide is wiped 

 with each piece of gauze. The surface to touch the slides should never have 



