228 PATHOGENIC BACTERIA. 



such an animal, the bacilli multiply at the point of in- 

 oculation, with the production of a patch of inflamma- 

 tion associated with a distinct fibrinous exudation and 

 the presence of an extensive edema. The animal dies in 

 twenty-four to thirty-six hours. The liver is enlarged, 

 and sometimes shows minute whitish points, which in 

 microscopic sections prove to be necrotic areas in which 

 the cells are completely degenerated and the chromatin of 

 their nuclei is scattered about in granular form. Similar 

 necrotic foci, to which attention was first called by Oertel, 

 are present in nearly all the organs in cases of death from 

 the toxin. The bacilli are constantly absent from these 

 lesions. Flexner has shown these foci to be common to 

 numerous irritant poisonings, and not peculiar to diph- 

 theria alone. 



The lymphatic glands are usually enlarged ; the adrenals 

 are also enlarged, and, in cases into which the live bacilli 

 have been injected, are hemorrhagic. 



Sometimes the bacilli themselves are present in the 

 internal organs, and even in the blood, but generally this 

 is not the case. 



It might be argued, from the different clinical pictures 

 presented by the disease as it occurs in man and in 

 animals, that they were not expressions of the same 

 thing. A careful study, however, together with the evi- 

 dences adduced by Roux and Yersin, who found that 

 when the bacilli were introduced into the trachea of 

 animals opened by operation a typical false membrane 

 was produced, and that diphtheritic palsy often followed, 

 and of hundreds of investigators, who find the bacilli 

 constantly present in the disease as it occurs in man, 

 must satisfy us that the doubt of the etiological role of 

 the bacillus rests on a very slight foundation. 



One reason for skepticism in this particular is the 

 supposed existence of a pseudo-diphtheria bacillus, which 

 has so many points in common with the real diphtheria 

 bacillus that it is difficult to distinguish between them. 

 We have, however, come to regard this pseudo-bacillus as 



