HANGING DROP 9 



it is well to pass the slides and cover-glasses through the flame of a Bunsen burner 

 or alcohol lamp to remove every vestige of grease. Ordinarily, rubbing between 

 the thumb and forefinger with soap and water, then drying with an old piece of 

 linen, and finally flaming will yield a perfect surface for making a bacterial 

 preparation. 



FIG. 2. i, Inoculation of tubes; 2, plugging of tubes; 3, filling tubes; 4, Smith's 

 fermentation tube; 5, Durham's fermentation tube. 



CONCAVE SLIDES, FERMENTATION TUBES. 



The concave slide is ordinarily used for making hanging-drop prep- 

 arations for the examination of bacteria as to motility, capsules, size 

 and arrangement. To prepare a hanging-drop preparation for the 

 study of motility it is best to place a loopful of the young bouillon 



FIG. 3. Hanging drop, over hollow ground slide. (Williams.) 



culture or a loopful of salt solution into which is then emulsified a 

 small amount of growth from an agar slant, in the center of the cover- 

 glass; now having applied with a brush a ring of vaseline around the 



