366 BACTERIA IN DIPHTHERIA. 



Its characters are given as follows : 



"The colonies of the pseudo -diphtheritic bacillus, cultivated upon blood 

 serum, are identical with the true diphtheria bacillus. At a temperature of 

 33 to 35 multiplication is rapid, and it continues at the ordinary tempera- 

 ture, although slowly. Under the microscope the appearance of the bacillus 

 which forms these colonies is the same as that of Bacillus diphtherias. It 

 stains readily with Loffler's solution of methylene blue, and intensely by 

 Gram's method. Sometimes it colors uniformly, at others it appears granu- 

 lar. It grows in alkaline bouillon, giving a deposit upon the walls of the 

 vessel containing the culture, and in this medium often presents the inflated 

 forms, pear-shaped, or club-shaped. It is destroyed in a liquid medium by a 

 temperature of 58 C. maintained for ten minutes. All of these characters 

 are common to the pseudo-diphtheritic bacillus and the true Bacillus diphthe- 

 riae. As a difference between them we may note that the pseudo- diphtheritic 

 bacillus is of ten shorter in colonies grown upon blood serum; that its cultures 

 in bouillon are more abundant ; that they continue at a temperature of 20 to 

 22, at which the true bacillus grows very slowly. When we make a com- 

 parison of cultures in bouillon they become acid and then alkaline, but the 

 change occurs much sooner in the case of the pseudo-diphtheritic bacillus. 

 Like the true bacillus, the pseudo- diphtheritic grows in a vacuum, but less 

 abundantly than the other. 



"Inoculations into animals of cultures of this bacillus have never caused 

 their death ; but we may remark that in some experiments a notable oedema 

 has been produced in guinea-pigs at the point of inoculation, while in others 

 there has been no local lesion. The most marked oedema resulted from cul- 

 tures obtained from cases of measles. 



' ' Do the facts which we have reported explain the question which occupies 

 us ? Can we conclude that there is a relation between the two bacilli ? On 

 the one side, the presence of the pseudo- diphtheritic bacillus in the mouths of 

 healthy persons, and of those who have anginas manifestly not diphtheritic, 

 seems to be opposed to the idea of a relationship between them. On the 

 other hand, when we consider that the non-virulent bacillus is very rare in 

 fatal diphtheria, that it is more abundant in benign diphtheria, that it be- 

 comes more common in severe cases as they progress towards recovery, and. 

 finally, that they are more numerous in persons who have recently had 

 diphtheria than in healthy persons, it is difficult to accept the idea that the 

 two microbes are entirely distinct. The morphological differences which 

 have been referred to are so slight that they prove nothing. The two micro- 

 organisms can only be distinguished by their action upon animals, but the 

 difference of virulence does not at all correspond with the difference of ori- 

 gin. As regards the form and the aspect of cultures, the true and false 

 diphtheria bacilli differ less than virulent anthrax differs from a very attenu- 

 ated anthrax bacillus, which, however, originate from the same source. 

 Besides, the sharp distinction which we make between the virulent and non- 

 virulent bacilli is arbitrary ; it depends upon the susceptibility of guinea- 

 pigs. If we inoculate animals still more susceptible, there are pseudo diph- 

 theritic bacilli which we must class as virulent; and if, on the contrary, we 

 substitute rabbits for guinea pigs in our experiments, there are diphtheritic 

 bacilli which we must call pseudo-diphtheritic. In our experiments we do 

 not simply encounter bacilli which are very virulent and bacilli which are 

 non- virulent; between these two extremes there are bacilli of every degree 

 of virulence." 



Abbott has recently (1891) published the result of his researches 

 with reference to the presence of the pseudo-diphtheritic bacillus in 

 benign throat affections. He made a bacteriological study of fifty- 

 three patients, nine of whom were suffering from acute pharyngitis, 

 fourteen from acute f ollicular tonsillitis, eight from ordinary post- 



