ESSAYS ON BACTEKIOLOGY. 39 



there is not difficult to account for, when it is remem- 

 bered that it cannot be surely recognized by micro- 

 scopic examination alone, and certain difficulties in its 

 cultivation are not always sufficiently heeded by all 

 observers." 



Frsenkel's bacteria are by no means exclusively 

 found in pneumonia. They are found in almost all 

 cases of cerebro-spinal meningitis, and the origin of 

 this affection is reasonably attributed to them. A. 

 Frsenkel has found them in pleuritis, Weichselbaum 

 in peritonitis, Banti in pericarditis, others have en- 

 countered them in endocarditis and otitis media and 

 numerous other affections. They occur especially in 

 the saliva and nasal secretions of healthy persons, as 

 established by Netter, and they may be regarded al- 

 most as regular tenants of these localities. Frsenkel's 

 diplococcus is indeed not the exciter of pneumonia 

 alone; its domain is more extensive; it does not restrict 

 itself to this one function. 



Fraenkel's bacterium is perhaps the principal ex- 

 citer of inflammatory processes of an infectious nature 

 in the human body. Wherever it reaches a serous or 

 mucous membrane and meets with the requirements 

 for its settlement, it commences operations. It causes 

 meningitis on the pia mater, peritonitis on the peri- 

 toneum, and otitis in the auditory passage. When- 

 ever it gains entrance into the lungs, pneumonia is de- 

 veloped, the peciiliar properties and characteristic pro- 

 cedure of which depend upon the peculiarities of the 



