68 THE GERM THEORY OF DISEASE. 



by the microscope, and the growth of the organisms is all 

 that is seen. This, when carried on from slide to slide, for 

 several generations, must disconnect the organisms from any 

 possible following of a chemical ferment. So palpable is this 

 demonstration that Billroth, Thiersch, and many others, who 

 had maintained a position of skepticism, have fully acknow- 

 ledged it. 



By use of these pure dry cultivations, Dr. Koch proved his 

 former experiments. He also obtained and cultivated the 

 bacillus anthrax by this mode; the bacillus of erysipelas, the 

 bacillus of leprosy, and some others of less note; and last 

 of all, that is as yet definitely announced, the bacillus of 

 tuberculosis. 



RESULTS. 



It will be seen that this work is only just begun. While 

 we have circumstantial evidence of the existence of very many 

 disease germs, only a few have been positively demonstrated 

 by isolation and pure cultivations, followed by inoculations 

 and the production of specific forms of disease. These are the 



Bacillus anthrax. 



Organism of chicken cholera. 



Bacillus of septicaemia. 



Micrococcus of pyaBmia. 



Cocco-bacterium of gangrene. 



Bacillus of erysipelas. 



Bacillus of tuberculosis. 



Bacillus of leprosy. 



Spirillum Obermeiri, the virus of relapsing fever. 

 Besides these, there are some others not so certainly demon- 

 strated. A considerable number of organisms are now pretty 

 well known by their continued association with a particular 

 form of disease, but have not yet been demonstrated by pure 

 cultivations and inoculations. The task of isolating one of 



