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 hours 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 
forexamination. 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 Baciuu1. 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 
‘‘balls’’ which it is seen to contain. From this make 
a cover-glass ‘‘smear’’ in the usual way. Immerse 
this in a solution of Ehilich’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 
