70 MOUNTING AND PREPARATION OP OBJECTS. 



Dissolve the aniline in the spirit ; rub up the 

 magenta in a glass mortar ; add the spirit gradually 

 while stirring, till all the colour is dissolved, then 

 add the water slowly, still stirring, and put in a 

 stoppered bottle. 



II. Saturated solution of chrysoiden in dis- 

 tilled water, to which is added a crystal of 

 thymol dissolved in a little absolute alcohol. 



This solution must be kept in a dark place. 



III. Commercial Nitric Acid, 1 part. 

 Distilled Water, 2 parts. 



The first two solutions must not be filtered. 



The solutions are used as follows : — 



The sputum is spread on a cover glass and al- 

 lowed to dry, it is then passed three or four times 

 through the flame of a spirit lamp, and left to cool. 

 A few drops of solution, number 1, are filtered into 

 a watch glass, and the cover glass, sputum down- 

 wards, placed on it, care being taken that no air 

 bubbles are under the cover glass ; it is allowed to 

 remain twenty minutes. It is then placed in the 

 acid solution, number 3, until the colour is removed 

 or about ten minutes. It is then washed in distilled 

 water until the nitric acid is removed, and then 

 placed in a little chrysoidin solution which has 

 been filtered into a watch glass, for a few minutes. 

 It must again be washed in distilled water, and the 

 superfluous water drained off on filtering paper ; it 

 is then placed in absolute alcohol and dried tho- 



