410 BACTERIOLOGY. 



necrosis of the tissues of the internal organs is of 

 comparatively rare occurrence. Caseation of the mes- 

 enteric glands, which is commonly observed, is due 

 probably to mixed infection. There are, however, a 

 number of cases now on record in which the typhoid 

 bacillus has played the part of pus producer. Cases 

 of sacculated and general peritonitis, subphrenic ab- 

 scess, osteomyelitis, periostitis, and inflammatory pro- 

 cesses of other kinds have been reported as being 

 due to the typhoid bacillus. Kruse also reports an 

 abscess of the spleen which contained only bacillus 

 typhosus, and typhoid abscess of the liver has been 

 recorded by many. In certain cases of typhoid pneu- 

 monia, serous pleurisy, empyema, and meningitis, 

 typhoid bacilli exclusively have occurred. The in- 

 flammation produced may or may not be accompanied 

 by the formation of pus. As argument against the 

 observations above cited there has been brought forward 

 the supposition that probably the real cause of the 

 disease had been destroyed before the entrance of the 

 typhoid bacillus. Though this may be true of some 

 cases, as in pneumonia, which is caused usually by the 

 short-lived pneumococcus, there is no reason to doubt 

 the causal relation of the typhoid bacillus to the other 

 diseases, inasmuch as it has been proved by numerous 

 investigations. 



Such cases, however, are of comparatively rare occur- 

 rence, because only exceptionally do the bacilli suffi- 

 ciently mass together in such numbers as to become 

 pus producers. As a rule, when complications occur 

 in typhoid fever they are due to secondary or mixed in- 

 fection with the staphylococcus, pneumococcus, strepto- 

 coccus, pyocyaneus, and colon bacillus. Frequently 



