PUS-MICKOBES IN SUPPUKATIVE AFFECTIONS. 99 



they have been deposited ID consequence of a secondary invasion. 

 The presence of streptococci in the pus from a suppurating pleural 

 cavity presents nothing characteristic, as the microbe is also found 

 in cases in which the empyema is secondary to pneumonia and 

 tuberculosis. On the other hand, he assigns to the pneumococcus 

 in pus removed from a pleural cavity a diagnostic significance, as it 

 proves, beyond all doubt, that the suppurative pleuritis occurred in 

 the course of a pneumonia as a secondary affection, consequently its 

 presence in the pus is positive proof that a pneumonia exists, or has 

 existed, even if the clinical and physical symptoms were not suffi- 

 ciently clear to indicate its existence. In four cases the empyema 

 had a tubercular origin, in two of which pneumothorax existed at 

 the same time. The presence of the bacillus of tuberculosis in the 

 pus is not easy to demonstrate, but the absence of this microbe is no 

 sign that the disease is not tubercular, as inoculations with such 

 pus in animals almost constantly produce typical tuberculosis. In 

 the pus of tubercular pyo-pnenmothorax, if microorganisms are 

 present, the bacillus of tuberculosis can be found, and the pus shows 

 no tendency to undergo putrefactive changes, in contradistinction 

 to empyema occurring in non-tubercular subjects, in whom spon- 

 taneous discharge through the bronchial tubes takes place. 



In the discussion on FrankePs paper, Senator maintained that 

 putrefaction is prevented by the parenchyma of the lungs acting as 

 a filter, preventing ingress of bacteria with the inspired air, and by 

 the presence of a large amount of carbonic acid gas in the air of the 

 cavity, as it is well known that microbes do not thrive as well in 

 such an atmosphere as in ordinary air. Fraukel believes that the 

 absence of putrefaction in such cavities is due to the fact that few, 

 if any organisms, except tubercle bacilli, are present in pus, a'nd 

 these do not cause putrefaction. It seems that tubercular pus does 

 not furnish a favorable soil for the growth of other germs. 



Ehrlich (Berl Uin. Woclienschrifi, May 14, 1888) has made a 

 bacteriological study of the pus in nineteen cases of empyema ; in 

 only seven of these could the bacillus of tuberculosis be found ; 

 in the remaining twelve this microbe could not be found, and upon 

 this negative ground the existence of tuberculosis was excluded. 

 Further observation in these cases after operation corroborated the 

 diagnosis. He asserts, therefore, that in the purulent pleuritic 

 exudation in tubercular patients, in empyema, and pyo-pneumo- 

 thorax, the presence of the specific- microbic cause can always be 

 demonstrated. In a case of pneumo-hydrothorax he failed to find 

 the bacillus until the effusion had undergone transformation into 

 pus, when its presence could be readily demonstrated. Some of the 

 pus-corpuscles contained as many as twenty bacilli. He places the 

 greatest importance on a bacteriological examination of the pus as a 



