379 

 AGGLUTINATION OF SPIROCHAETES 



Inject a rabbit, intravenously, on two or three 

 occasions with i-i c.c. of spirochaete blood. Its serum 

 will now agglutinate, render motionless and transform 

 into granules the corresponding spirochaete, but has no 

 action on other spirochaetes. Agglutination will occur 

 up to dilutions of I in 100. 



PFEIFFER'S PHENOMENON 



Inject a mouse, intraperitoneally, with o'l c.c. 

 of a specific spirochaete serum and J c.c. of blood 

 containing the corresponding spirochaete. The spiro- 

 chaetes disappear from the peritoneal cavity in ten 

 minutes, and the mouse does not become infected. If 

 any other but the corresponding spirochaete be used, 

 the spirochaetes are not destroyed and the mouse 

 becomes infected in twenty-four hours. 



\ 



Fig. 1 16 Sp. laverani 



5. Sp. laverani (Breinl, 1907). In the blood of 

 white and wild rats. In the fresh state it is an extremely 

 small, active spirochaete, shooting across the field, 

 revolving, turning, like a very active motile vibrio, and 

 not like other spirochaetes. Stained, it has two to six 

 spirals and is 2-6^ in length (Fig. 116). 



They are transmissible to mice and young rats only. 

 The infection may persist for months, though the 

 number of spirochaetes is then very small. 



