BACILLI PATHOGENIC IN MAN. 



Experiments As the result of experiments on animals which were 

 made with cultivations of Loeffler's bacilli, it was found 

 that mice and rats were immune against their action ; 

 guinea-pigs and small hirds died after subcutaneous in- 

 oculation, with the occurrence of a whitish or hsemorr- 

 hagic exudation at the seat of inoculation, and extensive 

 oedema of the subcutaneous cellular tissue. No micro- 

 organisms were found in the internal organs of these 

 animals. If the cultivations were applied to the trachea 

 of rabbits, fowls, and pigeons, characteristic and often 

 very extensive false membranes appeared. These formed 

 in like manner on the scarified conjunctiva of rabbits, 

 and at the entrance of the vagina of guinea-pigs. 

 Besides the false membranes, there also occurred a 

 bloody oedema, hemorrhages into the tissue of the lym- 

 phatic glands, and effusions into the pleural cavity. 

 Young animals, as a rule, succumbed to the infection 

 more readily and more quickly than older ones. 



Objections to The symptoms caused by the bacilli are thus very 



the etiological . ., , , . 



significance of similar to the morbid phenomena which are set up in 

 l ' man by the diphtheritic virus. Nevertheless, Loeffler 

 has hesitated to assume as a matter of certainty that 

 these bacilli are the sole specific exciting agents of 

 diphtheria, because they were not found in the false 

 membranes in a number of typical cases of diphtheria ; 

 because they were not present in the false membranes 

 developed in animals in the same typical arrangement 

 as was observed in man, but were, on the contrary, 

 either entirely absent or only present in small numbers ; 

 and, thirdly, because they could not be inoculated on 

 the healthy mucous membrane of susceptible animals, 

 but required the presence of small injuries before they 

 could cause infection. Nevertheless, it is quite possible 

 that the bacilli, whose great tendency to involution was 

 mentioned above, had already died in many of the 

 membranes, or had been eliminated, and were hence no 

 longer found ; further, that even in the case of man 

 trivial injuries of the mucous membrane may be necessary 

 to enable them to enter, and that thus these objections 

 do not exclude the possibility that these bacilli play a 



