1896 THE MICROSCOPE. 15 



of the sputum should be poured into a glass dish placed on a 

 dark background, and one of the characteristic yellowish parti- 

 cles picked out with a pair of fine-pointed forceps. This 

 should then be squeezed between two clear cover-glasses, the 

 films are allowed to dry in the air, and then passe<l three 

 times through the fiame of a spirit-lamp or Bunsen burner. 

 The glasses may then be floated on a warm carbol-fuchsine so- 

 lution for two to five minutes, washed rapidly in water to re. 

 move excess of fuchsine, decolorized in 25 per cent hydrochlo- 

 ric acid, w'ashe<3 in 60 to 70 per cent spirit till no more red 

 comes off. washed in water to remove spirit, dried between fil- 

 ter paper^and again pass through the flame three times. Next 

 stain in Loffler's methylene blue for ten to twenty seconds 

 wash once more in water, dry between filter paper, and again 

 pass through the flame. Finally, mount in xylol balsam, and 

 on examination the bacilli will be seen to be stained red on a 

 blue ground. It is suggested that the water, acid, spirit and 

 methylene blue should be kept in wide-necked, glass-stoppered 

 pots. The cover-glass is held in a pair of forceps, and passed 

 successively from one pot to another, thus effecting economy 

 both of time and material. 



Best Possible Illumination of the Microscopical Field. 



— The following })lan, says the editor of the National Druggist, 

 is not generally known, but in his experience it yields the best 

 possible illumination when using a condenser and wlien work- 

 ing with high-power objectives : After the object has been 

 placed on the stage and the instrument is in tlie desired posi- 

 tion, remove the ocular from the tube and look down the latter 

 with the naked eye. Whether you are using the mirror alone, 

 or the condenser, or whether you are working with natural or 

 artificial light, you will see a reversed image of the source of 

 illumination. Now, with the ocular still removed, arrange 

 your mirror or your condenser, or l)0th, so that you get the best 

 possible light, and that the illumination thus obtained shall be 

 as bright as possible over the entire field of vision. When op- 

 erating with natural light you will soon be able to throw upon 

 the object the spot of sky from which the light comes, and avoid 

 the mullions of the sash or castings of the windows through 

 which the light enters the room. If a lamp is used it w'ill be 

 but little trouble to l)ring the image of the flame directly into 

 the center of the field of vision. 



