180 THE AMERICAN MONTHLY [June 



7. Dehydrate in methylated spirit. 



8. Clear in clove oil. 



9. Mount in Canada balsam. 



Mounting in Canada Balsam. — Take three ounces of 

 dried Canada balsam and dissolve in three fluid ounces of 

 best benzole, filter and keep in a stoppered bottle. 



Clean a glass slide, take up a little balsam with a glass 

 rod and place a few drops on the centre of the slide, take 

 the section out of the clove oil on a lifter and place it in 

 the balsam on the slide. Clean a cover-glass, and with 

 the aid of a pair of fine forceps, carefully put the edge of 

 the cover into the balsam, ease it down so that no air bub- 

 bles may be included in the mount. When the balsam 

 has completely covered the under surface of the cover- 

 glass, press gently on its upper surface with the point of 

 the forceps, this will squeeze out any excess of balsam, 

 and set the section quite flat. Now put away for about 

 twenty-four hours to dry. 



When the balsam has dried, take a soft camel's-hair 

 brush with rather long hairs, and with a lit»le methyla- 

 ted chloroform carefully wash away the exuded balsam 

 from around the edge of the cover-glass, drain off the 

 chloroform and allow the slide to dry by exposure to air 

 only. When dry, place the slide in a turntable and run 

 on a ring of some good shellac cement. I have found an 

 enamel used for bicycles answer very well. As sold, it is 

 rather too thin for microscopical work, but this difficulty 

 is easily overcome by allowing it to evaporate for a few 

 days. Having applied a ring of cement, it must be allow- 

 ed to dry for about twelve hours, then take a piece of soft 

 rag and some turpentine, and carefully wash away any 

 trace of balsam and chloroform, dry with a clean cloth 

 and apply a second coat of enamel. 



