Microbic Diseases Individually Considered, 245 



gauism may be transported to another part by the 

 movements of the fluids in certain of the body cavi- 

 ties; virulent expectorations which are swallowed by 

 the diseased animal can thus infect the digestive 

 canal. 



The localization of the lesions is dependent upon 

 special predispositions of tissues or organs. This 

 fact has been demonstrated by the experiments of 

 Schuller, who showed that a contusion produced in 

 one of the articulations in a subject artificially in- 

 fected by any method whatsoever incites the evolu- 

 tion of a tubercular arthritis. 



Tubercular lesions may become purulent in the 

 absence of special pyogenic germs; the Koch bacil- 

 lus, therefore, secretes a pyogenic substance. The 

 injection of a culture in which the bacilli have been 

 killed by heat is followed by an abscess. 



Cultures sterilized and freed from bacilli are desti- 

 tute of all power of producing tubercles in healthy 

 individuals; when injected to tuberculous animals 

 they give the reaction of Koch's tuberculin. The 

 tubercular poison which occasions the specific neo- 

 plasms is, therefore, absent from the soluble portion 

 of the cultures; according to Straus and Gamaleia 

 it exists in the bacilli themselves and persists after 

 their death. Subcutaneous inoculation of dead ba- 

 cilli causes a local abscess. Intra-peritoneal inocula- 

 tion is followed by a tubercular peritonitis without 

 other lesion. Venous injection results in a pulmo- 

 nary tuberculosis in which the bacilli occur with 

 their special staining characteristics unimpaired, but 

 the tubercles thus obtained are not infective and have 

 no tendency to become generalized. When the dose 



