TEXT-BOOK OP BACTERIOLOGY. 335 



early as 1883, and therefore previously to Rosenbach and Passet's 

 statements, had obtained from osteomyelitic pus a micro-organism, 

 called by him the " micrococcus of acute infectious osteomyelitis," 

 but which was undoubtedly identical with the Staph, pyog. aureus 

 which was discovered later. 



All these experiments and conclusions have been subjected to crit- 

 icism. Grawitz, above all, on the strength of his own experiments, 

 in which he succeeded in injecting large quantities of living 

 staphylococci into the abdominal cavity of animals without any 

 subsequent symptoms of affection, positively a.sserts that the pyo- 

 genic bacteria are " not specific exciters of infection " like the an- 

 thrax bacilli, which thrive in the susceptible organism and infect it, 

 but that certain preparatory factors are required to enable the 

 staphylococci to enter the body and produce suppuration. The 

 special condition of an open wound, and mechanical as well as 

 chemical influences, must be considered; the excretions of the 

 pyogenic bacteria themselves were influential in the positive 

 experiments with animals, and were really the cause of suppuration 

 whenever the cocci were reproduced on a proper soil under natural 

 conditions. 



Much may be said against this view. A special predisposition 

 of the tissue, its peculiar tendency to retain bacteria, has also been 

 pointed out as a necessary condition for a perfect infection with 

 other micro-organisms, such as Frankel's diplococci, the diphtheria 

 bacilli, etc. In other micro-organisms, too, such as the cholera 

 vibrios, the t^'phus bacilli, etc., the symptoms of the disease as 

 well as the pathological changes were traced to the excretions of 

 the bacteria, but nobody denied their character as specific exciters 

 of infection. 



Leaving aside, however, these theoretical considerations, we do 

 not consider Grawitz's "facts" securely established. We should 

 be careful not to apply to man results obtained in animals, and 

 especially if we have to deal with a species a priori but little liable 

 to purulent processes. 



We must finally consider a circumstance wholly overlooked by 

 Grawitz. The staphylococci possess, like other micro-organisms, 

 a very varying degree of virulence and, besides, quickly succumb 

 to natural attenuation in our cultures. 



This circumstance is certainly of great importance in consider- 

 ing the striking diverse influences' of the staphylococcus, and we 

 can more readily understand why the same cause sometimes pro- 

 duces a furuncle, at other times endocarditis, and then again an 

 osteomvelitis. Other factors are also significant. The spot where 



