146 THE MORE CHRONIC INFECTIOUS DISEASES 



seems to kill them shortly, and weak solutions of the ordinary 

 disinfectants are quickly efficient. We assist in the clinical 

 diagnosis of chancroid by finding the diplo-rods, mostly 

 within leukocytes, in scrapings from the depth of the 

 ulceration. 



RELAPSING FEVER. 



Relapsing fever is caused by spirochetes whose species 

 differ in the various countries, Europe, Africa, India, and 

 America. The transmission is only known for the African 

 variety, which spreads by mea,ns of a tick. The spirochete 



FIG. 44. Spirocheta o bermeieri blood smear. Fuchsin. X 1000 

 diameters. (From Itzerott and Neimann.) 



circulates in the blood during attacks and settles in the spleen 

 between them. The disease is characterized by intermittent 

 attacks of continued fever beginning suddenly, lasting four 

 to six days, and ending by crisis. The febrile periods recur 

 with eight to ten days' intervals of freedom from symptoms. 

 Blood is examined during the fever and we find under the 

 microscope long, ^oVo i ncn > delicate, 50 Q 00 inch wide, wavy 

 spirals with corkscrew and undulatory movements. 



The spirochetes have been cultivated, under anaerobic 

 conditions, in serum supplied with fresh animal tissue and 

 these cultures may be transferred to monkeys and mice. 



