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CLINICAL BACTERIOLOGY. 



RELAPSING FEVER. 



The cause of relapsing fever was, in 1873, found by 

 Obermeier, a former assistant of Rudolph Virchow, and who 

 died prematurely, to be a special spiral bacterium, which 

 he designated the spirocheta of relapsing fever. Obermeier' s 

 discovery was the more far-reaching because with it an 

 organism of the class of bacteria was for the first time 

 recognized as the cause of a human infectious disease. 



The spirilla of relapsing fever {spirilla Obermeieri} are 

 delicate, wavy threads, with numerous turns (from ten to 

 twenty), varying in length from 16 to 40 /j., with distinctly 

 pointed extremities. In form and size they closely resemble 



Fig. 70. Bacillus of relapsing fever, from human blood; X 1000 (Giinther). 



cholera-spirilla, though they are only from one-half to one- 

 quarter as thick as these, and they never appear in the form of 

 a comma, or in S-shaped segments of a screw, but always only in 

 the form of a complete screw. The spiral thread can not be 

 differentiated into individual members. The spirilla possess 

 flagella and are actively motile. They glide in rapid, twisting 

 movements from one side to the other across the field of vision. 

 With regard to their propagation, nothing certain is known ; 

 probably this takes place by division. The formation of spores 

 has not been observed. 



Artificial cultivation of the spirilla of relapsing fever upon 

 nutrient media has thus far not been successful. The spirilla 

 must be looked upon as strict parasites that flourish only within 



