104 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 

 15 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. 



