508 



KELAPSING FEVEK 



' 



into short segments. They lose the stain in Gram's method. 

 There is no evidence that they form spores. 



Novy found that the spirochsete of American relapsing fever 

 remained alive and virulent in defibrinated rats' blood for 

 forty days. He also succeeded, by Leyaditi's method, in 

 obtaining cultures in collodion sacs containing rats' blood which 

 were placed in the peritoneum of rats. JSoguchi has succeeded 

 in cultivating the spirochetes of the various relapsing fevers by 

 the following method. A piece of sterile tissue, e.g., kidney of 

 rabbit, is placed in a test-tube ; a few drops of citrated blood 

 from an infected animal are added and then 15 c.c. of sterile 



ascitic or hydrocele fluid. 

 The presence of a loose 

 fibrin is helpful, and 

 growth occurs under or- 

 dinary anaerobic condi- 

 tions. He finds that all 

 the species multiply by 

 longitudinal and prob- 

 ably also by transverse 

 division. 



Relations to the Dis- 

 ease. — In relapsing fever, 

 after a period of incuba- 

 tion there occurs a rapid 

 rise of temperature which 

 lasts for about five to 

 seven days. At the end of 

 this time a crisis occurs, 

 the temperature falling 

 quickly to normal. In the 

 course of about other seven days a sharp rise of temperature again 

 takes place, but on this occasion the fever lasts a shorter time, 

 again suddenly disappearing. A second or even third relapse 

 may occur after a similar interval. The organisms begin to 

 appear in the blood shortly before the onset of the pyrexia, and 

 during the rise of temperature rapidly increase in number. 

 They are very numerous during the fever, a large number being 

 often present in every field of the microscope when the blood is 

 examined at this stage. They begin to disappear shortly before 

 the crisis : after the crisis they are entirely absent from the 

 circulating blood. A similar relation between the presence of 

 the organisms in the blood and the fever is found in the case of 

 the relapses. Munch in 1876 produced the disease in the 



Fig. 152. — Spirochetes of relapsing fever in 

 human blood. Film preparation. (After 

 Koch.) See also Plate IV., Fig. 18. 

 x about 1000. 



