IO4 , Appendix B. 



solution in a watch-glass ; place the cover-glass, with the 

 sputum downwards, on the stain, taking care that there are no 

 air-bubbles under it. Let it remain for fifteen or twenty 

 minutes ; then wash in the dilute acid till all colour has dis- 

 appeared. Remove the acid with distilled water ; then place the 

 cover-glass in the same manner as before on a few drops of 

 chrysoidin, filtered into the bottom of a watch-glass, and let it 

 remain for a few minutes till it has taken a brown stain. Wash 

 off the superfluous colour in distilled water, and place the cover- 

 glass in absolute alcohol for a few minutes. Then remove and 

 dry perfectly in the air, and mount in a solution of Canada 

 balsam. The Bacilli are visible with a quarter-inch objective. 

 (See Lancet, ii., 1882, p. 183.) By this process only B. tuber- 

 culosis is stained, the ordinary putrefactive bacteria remaining 

 colourless. 



Prideaux (I.e., p. 1138) uses methylene-blue instead of 

 chrysoidin for staining the ground ; by this means the Bacilli 

 show up red on a blue background. The process may fail if the 

 solutions are at a lower temperature than 100 F., and Professor 

 Brun recommends that the sputum should not be exposed to a 

 greater heat than 176 F. If gentian violet be used, after the 

 nitric acid treatment, the putrefactive bacteria will be stained, 

 and not the tubercle bacilli, which are thus strongly differ- 

 entiated. The latter are also stained by fuchsin. 



The following is Heneage Gibbes's rapid method of demon- 

 strating B. tuberculosis without nitric acid. Take of rosaniline 

 hydrochloride 2 grm., methyl -blue I grm. ; rub in a glass 

 mortar. Then dissolve aniline oil 3 c. cm. in rectified spirit 

 1 5 c. cm. ; add the spirit slowly to the stain till all is dissolved ; 

 then slowly add distilled water 15 c. cm.; and keep in a stop- 

 pered bottle. Place a few drops of the stain in a test-tube, 

 and warm ; as soon as steam rises, pour into a watch-glass, and 

 place the cover-glass as before. After four or five minutes wash 

 in methylated spirit till no more colour comes away ; drain 

 thoroughly, and dry either in the air or over a spirit-lamp. 

 Mount in Canada balsam. A section of tissue containing Bacilli 

 can be treated in the same way, only it must be left in the stain 

 for several hours. 



