OCCURRENCE OF CAUSATIVE AGENTS. 131 



complex of erysipelas. Cases are, however, on record in 

 which it was possible to cultivate streptococci from the 

 blood of patients ; general infection, therefore, having existed. 



Immunity. Recovery from one attack of erysipelas 

 confers no immunity to subsequent attack. Erysipelas is 

 one of the diseases attended with numerous recurrences. 

 The blood-serum of persons just recovered from an attack 

 of erysipelas does, however, at times possess immunizing 

 properties ; and large amounts thereof may, according to 

 some reports, immunize animals (guinea-pigs and mice) 

 to streptococci. 



Experimental Evidence of the Etiologic Significance 

 of the Streptococcus for the Development of Erysipelas. 

 The introduction of streptococcus-material into shallow, 

 superficial wounds of rabbits' ears is followed by the devel- 

 opment of erysipelatous inflammation. Much more im- 

 portant are the observations that have been made in human 

 beings. Proceeding from the clinical experience that in 

 individuals with advanced lupus or with inoperable tumors 

 an attack of intercurrent erysipelas may lead to the cessa- 

 tion, or even the cure, of the original disease-process, it 

 was ventured in such cases to undertake cutaneous inocu- 

 lations with streptococcus-cultures derived from cases of 

 erysipelas. These experiments yielded positive results : 

 typical erysipelas pursuing a characteristic course occurring 

 almost constantly. A similar result was attained by Koch 

 and Petruschky by means of a streptococcus derived from 

 a purely suppurative process. There is no doubt that a 

 therapeutic influence is exerted by several streptococcus- 

 infections upon the course of carcinoma, but the strength 

 of the patient suffers so much in consequence of the inocu- 

 lations with erysipelas that a practical application of this 

 method is entirely out of consideration. 



The Occurrence of Other Microorganisms in Erysipe- 

 las. In two cases of true erysipelas (the second infected 

 by the first) Jordan cultivateol.the staphylococcus pyogenes 

 aureus. From this it may be concluded that the other 

 causative agents of inflammation are capable, under certain 

 circumstances, of inducing erysipelas. The usual cause, 

 however, is without question the streptococcus. 



The bacteriologic diagnosis of erysipelas is only most 

 rarely necessary. In such an event a small scarification is 

 made with a sterilized lancet at the border of the inflamma- 



