302 BACTERIOLOGY. 



the name of the patient or other distinguishing mark. 

 The expectoration discharged in the morning is to be 

 preferred, especially in recent cases, and the material 

 should be coughed up from the lungs. Care should be 

 taken that the contents of the stomach, nasopharyngeal 

 mucus, etc., are not discharged during the act of expec- 

 toration and collected instead of pulmonary sputum. If 

 the expectoration be scanty the entire amount discharged 

 in twenty-four hoars should be collected. In pul- 

 monary tuberculosis the purulent, cheesy, and muco- 

 purulent sputum usually contains bacilli; while pure 

 mucus, blood, and saliva, as a rule, do not. When 

 hemorrhage has occurred, if possible some purulent, 

 cheesy, or mucopurulent sputum should be collected 

 for examination. The sputum should not be kept any 

 longer than necessary before examination, for, though 

 a slight delay or even till putrefaction begins, does not 

 entirely vitiate the result, it is best to examine it in as 

 fresh a condition as possible. 



2. Methods of Examination, (a) EXAMINATION FOR 

 TUBERCLE BACILLI. Pour the specimen into a clean, 

 shallow vessel having a blackened bottom a Petr 

 dish placed upon a sheet of dull black paper answers 

 the purpose and select from the sputum one of the 

 small, white or yellowish-white, cheesy masses or 

 11 balls " which it is seen to contain. From this make 

 a cover-glass " smear " in the usual way. Immerse 

 this in a solution of Ehrlich's aniline-water fuchsin (see 

 page 198), contained in a thin watch-glass or porcelain 

 dish, and steam over a small flame for two minutes. 

 Then remove the cover-glass from this and wash with 

 water. Now decolorize by immersing the stained prep- 

 aration in a 3 per cent, hydrochloric acid solution in 



