542 BACTERIOLOGY. 



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 locally, and is from that point distributed 

 to the distant organs. Has the specific germ of diph- 

 theria any property to warrant such a view ? 



If a fluid culture of bacillus diphtheria be filtered 

 through a porcelain filter, the filtrate will contain none 

 of the bacteria. If this filtrate, free of all bacteria, be 

 injected into animals, death ensues ; and if the tissues of 

 this animal be examined, all of the most important 

 lesions that characterized the tissues of the animal dead 

 after inoculation with the living germ are to be found. 



If a parallel experiment be made with the bacillus of 

 tetanus analogous results will be obtained. 



It is clear, then, that here are two species of bacteria 

 that excite the characteristic results through the instru- 

 mentality of a something that they manufacture in the 

 course of their growth ; that may be separated from them 

 by the simple process of filtration, and that when so 

 separated possesses all the properties of specific intoxi- 

 cants. 



In anthrax and other septicaemias we saw that, nor- 

 mally, the infection was characterized by the distribution 

 of the bacteria throughout the body, but that modified 

 results, differing only in degree, might still be obtained 

 with the attenuated organisms without such general dis- 

 tribution. These latter conditions must, therefore, have 



