346 APPLIED IMMUNOLOGY 



originally associated only with a characteristic cutaneous 

 eruption following antisyphilitic treatment, at one time — 

 before the discovery of the treponema pallidum and the Was- 

 sermann reaction — enjoyed considerable importance as a 

 diagnostic aid. The skin and mucosa reactions are mani- 

 fested by oedema, swelling, redness, pain and other inflam- 

 matory signs. To-day the Herxheimer reaction is regarded 

 to be much broader in its scope and may be defined as a cu- 

 taneous eruption, an aggravation of a pre-existent syphilitic 

 roseola or any inflammatory reaction in syphilitic tissue pro- 

 voked hy the administration of salvarsan, neosalvarsan or 

 mercury. This is to be distinguished from the arsenic rash in 

 non-syphilitics receiving salvarsan. Various manifestations 

 of the reaction are apparent. The increased redness of the 

 roseola, the inflammatory reaction in mucous patches, the 

 swelling, exudation and occasional ulceration of gummata 

 observed a few hours or a day or so after medication, the 

 lancinating pains of tabes dorsalis, augmented or relighted, 

 as observed following the Swift-Ellis treatment, the so-called 

 neuro-recurrences and the provocative positive Wassermann 

 reaction are all evidences of the Herxheimer reaction in whole 

 or in part. 



According to Ehrlich the occurrence of these phenomena 

 is due to treatment dosage insufficient to destroy completely 

 the treponemata pallida whereby the escaped viable or- 

 ganisms are sensitized or stimulated to increased activity. 



Excretion of Salvarsan from the Body. — The elimination 

 of salvarsan from the system has been carefully studied both 

 on the human and on lower animals. It has been determined 

 by urinalysis and gastric analysis that the elimination of 

 the drug occurs almost immediately following its intravenous 

 administration, while after intramuscular injection it is sel- 

 dom detected for an hour, although after subcutaneous in- 



