540 BACTERIOLOGY. 



Similiarly, in other varieties of septicaemia, the so- 

 called " hemorrhagic group " we see as a rule typical, 

 fatal septicaemias resulting from the invasion of the 

 body by the organisms causing them ; but at times, 

 through influences not fully known, these organisms 

 become modified in their physiological functions so that 

 instead of the customary general invasion of the circu- 

 lating fluids there may be only a very slight invasion 

 and the results of their inoculation are principally 

 evidenced as local destruction of tissue, sometimes with 

 fatal results. Obviously then these organisms have the 

 power of causing constitutional disturbances, tissue 

 changes and even fatal results without the necessity of 

 their dissemination throughout the body by way of the 

 circulating fluids. 



As said above the characteristic lesion of tuberculosis 

 is the tubercle, and the peculiarity of the tubercle is 

 necrosis, observable almost from the moment it begins 

 to develop. If tuberculosis be induced through the 

 intravenous injection of rabbits with carefully prepared 

 suspensions of virulent tubercle bacilli the resulting 

 miliary tubercles, discernable from their very incip- 

 iency, are always marked by more or less death of 

 tissue at and about their centre, which tissue death pro- 

 gresses as the disease progresses, until it reaches a point 

 easily seen with the naked eye and incompatible with 

 life. If on the other hand a similar injection be made 

 with a suspension of tubercle bacilli that have been 

 killed, by heat or otherwise, disseminated nodules, 

 tubercles, will also be found in the internal organs. 

 These may be histologically strikingly like those follow- 

 ing the use of the living organism ; they are marked by 



