§ XIII.] Relapsing fever. 151 



are constantly confronted in dealing with the main points of our 

 subject with similar facts and questions to those which were 

 considered at some length in connection with anthrax and fowl- 

 cholera ; they form part of the great series of facts and questions 

 relating to parasitism, of which it was attempted to give a con- 

 cise review in Lecture X. 



With this brief reference to these previous expositions we now 

 proceed to consider a few comparatively well-known cases. 



2. Relapsing fever, febris recurrens (59), is a disease which is 

 widely spread in Asia and Africa, is endemic in Russian Poland 

 and Ireland, and sometimes finds its way into other countries 

 of Europe. It is communicated directly from the body of one 

 person to another or through the intervention of articles of daily 

 use. In 5-7 days after infection violent fever sets in with other 

 symptoms which need not be described here, and usually lasts 

 another 5-7 days, and is then followed by a period of absence 

 of fever for about the same number of days. Then comes a 

 relapse into the fever state, and the same alternation may be 

 repeated several times, usually with a favourable ending. 



During the attack a slender Spirillum, resembling Spirochaete 

 Cohnii (Fig. 16, e), sometimes 40 /u in length and exhibiting 

 active movements, is found in abundance in the blood of the 

 patient which is often of a dark -red colour; discovered by 

 Obermeier in 1873 it was named after him Spirochaete Ober- 

 meieri ; it disappears during the interval when there is no fever. 



The disease is conveyed to men and monkeys when they are 

 inoculated with the blood of a fever-patient containing Spiro- 

 chaete. Blood taken during the interval of freedom from fever 

 and therefore free from the Spirochaete does not produce the 

 disorder after inoculation^ Experiments in the inoculation of 

 other animals were always without result. Attempts to cultivate 

 the Spirochaete outside the body of the animal have not as yet 

 been successful. 



From these facts it may properly be assumed that tjie Spiro- 

 chaete is the contagium of relapsing fever, though we are still 



