346 BACTERIA IN INFECTIOUS DISEASES. 



in the circulating blood; in other words, by true em- 

 bolism." 1 



RELAPSING FEVER. The presence in the blood 

 of patients suffering from relapsing fever of a 

 parasitic micro-organism of spiral form, and ex- 

 hibiting active movements, was discovered by 

 Obermeier in 1868. Since this date numerous ob- 

 servers have confirmed the discovery, and have 

 verified the fact that this parasite is uniformly 

 found in the blood, in this disease, when the fever 

 is at its acme, both during the first invasion and 

 the relapse. It disappears very quickly, how- 

 ever, when defervescence occurs. These spiral 

 filaments (see Fig. 3, Plate X.) are extremely 

 slender, the diameter never exceeding 1 p.. Their 

 length is from 150 to 200 p.. 



" Their motion is very lively, rotatory, twisting, and 

 rapidly progressive ; but soon ceases under the ordinary 

 conditions of microscopic examination. As the blood 

 under examination cools and begins to coagulate, these 

 movements become slower, and many spiral filaments 

 become covered with very fine threads of fibrin e " 

 (Lebert). 



Inoculation of monkeys with the blood of re- 

 lapsing fever-patients has been successfully prac- 

 tised by Koch and by Carter. Both of these 

 experimenters have also succeeded in cultivating 

 the spirochsete external to the living body. 



1 Traumatic Infective Diseases, Sydenham Society's translation, p. 51. 



