THE BACILLUS OF TUBERCULOSIS 



with the tubercle bacillus should, also be determined. It is now usual 

 to distinguish pure tuberculosis of the lungs from a mixed infection. 

 Phthisis due to the tubercle bacillus alone, which constitutes but a 

 small percentage of all cases, may occur almost without febrile reac- 

 tion; or when fever occurs the prognosis is unfavorable, thus indicating 

 that the disease is already advanced. It is in the uncomplicated forms 

 of phthisis, moreover, where one must expect if anywhere the best results 

 from treatment with tuberculin or antituberculous serum. The majority 

 of cases, however, of pulmonary tuberculosis show a mixed infection, 

 especially with varieties of the streptococcus and pneumococcus. These 

 cases may be active, with fever, or passive, without fever, according, 

 perhaps, as the parenchyma of the lung is invaded by the bacteria; or 

 they are only superficially located in cavities, bronchi, etc. Mixed 

 infection with the staphylococcus, other micrococci, and with the influ- 

 enza bacilli have also been frequently met with by us. The tetragenus 

 has not been often detected by us in thoroughly washed fresh sputum. 

 At present the facts seem to prove that the tubercle bacilli have in the 

 great majority of cases, at least until shortly before death, a much more 

 important role than the associated bacteria. 



Sputum Washing. Some of the associated bacteria found in the 

 expectoration come from the diseased areas of the lungs, while others 

 were merely added to the sputa as it passed through the mouth, or 

 have developed after gathering. To endeavor to separate the one 

 from the other we wash the sputa. The first essential is that the mate- 

 rial be washed within a few minutes, and certainly within an hour, of 

 being expectorated. If a longer time is allowed to intervene, the bac- 

 teria from the mouth will penetrate into the interior of the mucus, and 

 thus appear as if they came from the lungs. Sputum treated twenty- 

 four hours after its expectoration is useless for examining for anything 

 except the tubercle bacillus. A rough method is to pour some of the 

 specimen of sputum to be examined into a convenient receptacle con- 

 taining sterile water, and withdraw, by means of a sterilized platinum 

 wire, one of the cheesy masses or thick "balls" of mucus. Pass this 

 loop five times through sterile water in a dish; repeat the operation in 

 fresh water in a second and third dish. Spread what remains of the 

 mass on cover-glasses and make smear preparations; stain and examine. 

 With another mass inoculate ascitic bouillon in tubes and agar in plates. 



When we wish to thoroughly exclude mouth bacteria, a lump of the 

 sputum raised by a natural cough is seized by the forceps and trans- 

 ferred 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 Infection. 1. The 

 difficulties to be overcome, in order to obtain sputum consisting pre- 



