590 BACTERIA IN INFECTIOUS DISEASES. 



ganism obtained in his cultures or seen in stained preparations of 

 pus from the pleural cavity. In a second group of three cases, oc- 

 curring in the course of a pneumonia, the only microorganism pres- 

 ent was " diplococcus pneumonia? " (Micrococcus pneumonia? crou- 

 posa?). The third group included four cases of tubercular emp3 r ema; 

 in one of these tubercle bacilli only were found in pus from the 

 pleural cavity, in one case streptococci were found, and in two no 

 microorganisms were found. In the fourth group of two cases the 

 empyema resulted from the opening of an abscess into the pleural 

 cavity, and streptococci were found in the pus. 



Netter, in a series of forty-six cases examined by him, found Mi- 

 crococcus pneumonia? crouposa? in fourteen. Koplik (1890) found 

 the same microorganism in seven cases examined by him, and Strep- 

 tococcus pyogenes in two cases. 



Weintrand (1893) has reported a case of empyema following ty- 

 phoid fever, in which the typhoid bacillus in pure culture was found 

 in pus drawn from the pleural cavity by means of a syringe. 



Prudden (1893) found microorganisms in every case examined by 

 him (twenty-four) ; in seven cases out of eight Streptococcus pyo- 

 genes was present in pus obtained from the pleural cavity. In the 

 cases of metapneumonic empyema the germ most commonly present 

 (in nine cases out of eleven) was the Micrococcus lanceolatus (pneu- 

 mococcus). In four cases of foetid empyema various bacilli were 

 found. Staphylococcus pyogenes aureus was present in one case 

 only. 



Levy (1895), from a review of the literature of the subject in 

 connection with his own observations, arrives at the conclusion that 

 Streptococcus pyogenes is the usual cause of purulent inflammation 

 of the pleura found in sixty per cent of the cases. 



ENDOCARDITIS. 



The experimental evidence relating to endocarditis is similar to 

 that in cystitis. The injection of the microorganisms found attached 

 to the diseased structures into the circulation of lower animals does 

 not produce endocarditis unless the valves have been previously in- 

 jured by mechanical violence or by chemical irritants. If some 

 doubt remains among pathologists as to the etiological relation of the 

 microorganisms found, the serious secondary results of the mycotic 

 invasion are well established. In a series of twenty-nine cases stud- 

 ied by Weichselbaum (1885-1888) the following results were ob- 

 tained : In eight the result of culture experiments and microscopical 

 examination was negative; in seven "diplococcus pneumonia?" (Mi- 

 crococcus pneumonia? crouposa?) was found; in six Streptococcus 



