

BACILLUS OF TUBERCULOSIS. 307 



When we wish to thoroughly exclude mouth bacteria 

 a lump of the sputum raised by a natural cough is seized 

 by the forceps and transferred to a bottle of sterile 

 water and thoroughly shaken ; it is then removed to a 

 second bottle of bouillon and again thoroughly shaken. 

 From this it is passed in the same way through four 

 other bottles of bouillon. A portion of the mass is 

 now smeared over cover-glasses, and the rest inoculated 

 in suitable media, such as agar in Petrie dishes, and 

 ascitic fluid bouillon in tubes. If desired the bacteria 

 washed . off in the different washings are allowed to 

 develop. 



Practical Notes on the Examination for Mixed Infec- 

 tion. 1. The difficulties to be overcome, in order to 

 obtain sputum consisting presumably of exudate from 

 the deeper portions of the lungs, are so great that the 

 collection of the specimens should be supervised by the 

 bacteriologist in charge of the work of examination. 



2. Specimens of sputum collected even with the 

 greatest precaution may give evidence of decided 

 mouth infection unless immediately washed. 



3. The sputum must be examined very soon after 

 collection. 



4. The culture medium used for the final cultures 

 must be suitable for the growth of the micro-organisms. 



5. At least two successive examinations of sputum 

 should be made in each case. 



6. The results, especially as to the number of colo- 

 nies, vary according to the size and tenacity of the ball 

 of sputum washed e.g., a small ball of sputum which 

 becomes more or less broken up upon thorough shaking 

 may contain very few or no bacteria. 



Williams, in the examination of the sputum in some 



