298 BACTERIA. 



parts of the body, giving rise to heart failure, or to certain 

 forms of paralysis, partly through its action on the nervous 

 system and partly owing to its interference with the 

 nutrition of the various tissues of the body. Here again, 

 however, those who were studying the subject were con- 

 fronted with another difficulty ; there were so many forms 

 of micro-organisms that found in this false membrane a suit- 

 able subsoil on which to grow, it was almost impossible 

 with the methods then at command to separate them and so 

 to obtain pure cultures, in order that the specific and bio- 

 logical characters of each might be investigated. 



In 1875 Klebs found in the false membranes a small bacillus 

 with rounded ends, and with, here and there, small clear spaces 

 in its substance, a bacillus that was not readily stained, that 

 grew luxuriantly in broth, and which, inoculated into animals, 

 gave rise to a peculiar dirty fibrinous-looking slough at 

 the seat of inoculation. He found, however, that in certain 

 cases this bacillus was absent, the predominating organism 

 then seeming to be a micrococcus arranged in masses or in 

 short chains. This, when cultivated in broth, gave rise to 

 the formation of chains of considerable length. As a result 

 of these observations he described diphtheria as occurring in 

 two forms, one form resulting from the action of one organ- 

 ism, the second being caused by the other. 



These researches were continued by other workers, and 

 Formad, in America, came to the conclusion that the rod- 

 shaped bacillus had little to do with the disease, but 

 that the streptococcus, or chain-forming micrococcus, was 

 the real exciting cause. Matters remained at this stage 

 for some time in fact, until Loffler took up the subject. 

 After examining a number of cases of diphtheria, he found 

 that, although there are numerous organisms in the false 

 membranes or diphtheritic patches, these were mostly near 

 the surface, and many of them were simply the organisms 

 that were usually found in the mouth now growing under 

 more favourable conditions of nutrition. He found, however, 

 that in the deeper layers, or at the inner margin of the layer 

 of exudation, the Klebs bacillus might almost invariably be 

 found. It was more deeply situated than any of the others, 

 and was always most numerous in the oldest part of the 

 membrane. This was in cases of pure diphtheria. In the 

 so-called diphtheritic sore throats met with in other diseases, 



