until thoroughly iried. It is then passed three times 

 through the flame it intervals of about one second. 



3. STAmiNG THE COVER-GLASS. 



(a) Holding the cover-slip 'Tsutter" side up horizon- 

 tally in the forceps, the glass is flooded to its edges with 

 a pipetteful of the desired staining fluid. 



(b) Allow the fluid to remain from one-fourth to 

 one-half a minute upon the slip, or the staining may be 

 hastened by heating the slip until a light steam arises. 



(c) Wash the slip in water. If gentian-violet and 

 fuchsin are used it is better if the wash water contains 

 from one-third per cent, to one-fourth per cent, of acetic 

 acid. Afterward, however, wash the slip thoroughly in 

 pure water. 



4. EXAMINATION OF THE STAINED COVER-GLASS. 



(a) Lay the just washed cover-glass upon a slide 

 ("butter" side down); absorb the superfluous water by 

 placing a folded strip of filter-paper upon both slip and 

 slide, and by lightly running the finger-tips over the same. 

 Holding the cover in place with the thumb naU, remove 

 aU moisture from the surface of the cover with a corner 

 of the filter-paper. Examine with the microscope (placing 

 a smaU drop of cedar-oil in the centre of the cover if de- 

 sirous of using an oil-immersion lens). Or: 



(b) Thoroughly dry the cover-glass first by pressing 

 it between two folds of filter-paper and then by holding 

 it above the flame. Place a small drop of Canada balsam, 

 thinned with xylol, in the centre of the slide and place 

 the cover-slip upon it. Preparations, examined first in 

 water, may then be thus mounted in balsam, after 

 first removing the cedar-oil with filter-paper moistened 

 with xylol, and then removing the cover-glass from the 

 slide. 



15 



