OCCURRENCE OF CAUSATIVE AGENTS. 129 



cereus albus are obtained. These observations with regard 

 to the common exciting agents of inflammation explain the 

 clinical fact that the most variable suppurative processes 

 furunculosis, etc. sometimes precede and sometimes follow 

 the actual attack of impetigo. 



Ecthyma. This also is a form of cutaneous suppura- 

 tion in which the pyogenic cocci are found. From the pus 

 staphylococci and streptococci have been cultivated. 



Herpes. Herpes zoster has been designated by Pfeiffer 

 (Weimar) an infectious disease whose causative agent 

 belongs to the class of protozoa. The cells believed by 

 Pfeiffer to be protozoa have, however, not received recog- 

 nition, and, above all things, it has as yet been impossible 

 to cultivate them. In the vesicles that become turbid 

 staphylococci and streptococci are always found, while the 

 contents of the clear vesicles are often sterile. 



In cases of herpes labialis the vesicles contain the excit- 

 ing agents of inflammation from the beginning, and more 

 frequently streptococci and Frankel's diplococci than 

 staphylococci. According to Pfeiffer, protozoa are absent 

 in this form of herpes. As soon as the contents of the 

 vesicles are turbid, staphylococci will be found present 

 therein, and partly in association with streptococci, partly 

 alone. These observations suggest that herpes labialis is 

 not a true zoster. In general it occurs only as a complica- 

 tion of such infectious diseases as themselves stand in etio- 

 logic relation with the common exciting agents of inflam- 

 mation (pneumonia, meningitis, etc.) ; it may, perhaps, be 

 viewed as a secondary localization of the causative agent 

 of the primary process. 



In herpes of the pharynx (angina herpetica) and of the 

 larynx the same conditions seem to prevail as in herpes 

 labialis. 



ERYSIPELAS. 



Erysipelas is excited by the streptococcus. The old 

 discussion whether or not the streptococcus erysipelatis 

 (Fehleisen) is distinct from the streptococcus pyogenes, the 

 exciting agent of suppuration, can now be considered as 

 finally decided. The two microorganisms are without doubt 

 identical. This is demonstrated as well by their complete 

 agreement in morphologic and cultural peculiarities, as also 

 by the results of experiments on animals and man. 

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