XVII. 

 PATHOGENIC SPIRILLA. 



SPIRILLUM OBERMEIERI. 



Synonyms. Spirochaete Obermeieri ; Spirillum of relapsing fe- 

 ver ; Die Recurrensspirochate. 



Discovered by Obermeier (1873) in the blood of persons suffering 

 from relapsing fever. 



This spirillum is present, in very great numbers, in the blood of 

 relapsing-fever patients during the febrile paroxysms. It has not 

 been found under any other circumstances, and its etiological rela- 

 tion to the disease with which it is associated is generally admitted. 



Morphology. Very slender, flexible, spiral or wavy filaments, 

 with pointed ends ; from sixteen to forty /* in length and consider- 

 ably thinner than the cholera spirillum about 0.1 /*. Koch has 

 demonstrated the presence of flagella (Eisenberg). 



Stains readily with the aniline colors, especially with fuchsin, 

 Bismarck brown, and in Loffler's solution of methylene blue. 



Biological Characters. An aerobic, motile spirillum which 

 has not been cultivated in artificial media. This spirillum appears to 

 be a strict parasite, whose habitat is the blood of man. The disap- 

 pearance of the parasite from the blood soon after the termination 

 of a febrile paroxysm, and its reappearance during subsequent par- 

 oxysms, have led to the inference that it must form spores, but this 

 has not been demonstrated. In fresh preparations from the blood 

 the spirillum exhibits active progressive movements, accompanied 

 by very rapid rotation in the long axis of the spiral filaments, or by 

 undulatory movements. The movements are so vigorous that the 

 comparatively large red blood corpuscles are seen, under the micro- 

 scope, to be thrown about by the slender spiral filaments, which it is 

 difficult to see in unstained preparations. When preserved in a one- 

 half -per-cent salt solution they continue to exhibit active movements 

 for a considerable time. Efforts to cultivate this spirillum in artificial 

 media have thus far been unsuccessful, although Koch has observed 

 an increase in the length of the spirilla and the formation of a 

 tangled mass of filaments. 



