270 BACTERIOLOGY 



only in degree from that caused by the same species when 

 living and fully virulent. 



A similar property may be demonstrated in a number of 

 other pathogenic species in no way related to bacillus tuber- 

 culosis. Obviously, there is something within or associated 

 with these bacteria that may act upon the tissues even 

 though the bacteria themselves may be dead. 



In our autopsy on the animal dead of diphtheria we saw 

 that the bacilli were not distributed throughout the body, but 

 were confined to the site of inoculation. We saw at the 

 site of inoculation a tissue reaction scarcely sufficient to 

 account for the fatal result, yet that result occurred within 

 a comparatively short time after inoculation. 



When diphtheria occurs in human beings the same holds 

 true as a rule, and while occasionally the local reaction in 

 the throat is such as gravely to imperil life through obstruc- 

 tion to respiration, the real danger in most cases is not local 

 but remote, and the clinical observations on the living subject 

 affected with this disease point to the far-reaching influence 

 of a local phenomenon, that, of itself, may often seem to be 

 of but slight significance. 



If the internal organs of either animals or human beings 

 that have died of diphtheria be examined microscopically, 

 changes are easily to be discovered that are incompatible 

 with life and that at once account for many of the clinical 

 manifestations of the disease, yet these changes are not 

 accompanied by the presence of bacteria nor by any other 

 agent that can be detected by the eye. 



It is plain, then, that the serious influence of the local 

 infection of diphtheria is referable to a something that 

 originates at the point where the bacteria are growing and is 

 from that point distributed to the distant organs. 



