SPIROSCHA UDINNIA 



441 



fully developed spirochaetes. Infection takes place towards the end of feeding 

 by the excretion from the Malpighian tubules, which contains the spirochaetes, 

 passing into the wound caused by the bite. 



Some of the Spiroschaudinnics , on entering the tick, pass into the cells by 

 the alimentary canal, and undergo multiple transverse division, while others 

 may live for some weeks in the gut. 



Cultivation. — Noguchi has successfully cultiv^ated 5. duttoni in 

 sterile ascitic or hydrocele fluid, to which a piece of fresh rabbit's 



$® ®® ® o 



Fig. 127. — Schizogony of Spiroschaudinnia mavchouxi Nuttall. 

 (After Sambon.) 



kidney has been added. For inoculation of this medium he uses a 

 few drops of the citrated heart blood from a mouse forty-eight to 

 seventy-two hours after infection. 



Fig. 128. — Development of 5. 

 Duttoni. (X 1,000.) 



The small dots are chromatin bodies 

 and the large granules are digested 

 blood, while the pale outlines are 

 spirochaetes in the contents of the 

 intestinal sac of a tick two days after 

 an infective feed. (From a micro- 

 photograph by Sir William Leishman.) 



Fig. 129.- — Chromatin Granules in 

 THE Malpighian Tubule of a 

 Tick Six Days after Infective 

 Feed. (X 1,000.) 



(From a microphotograph by Sir 

 William Leishman.) 



At a temperature of 37° C. the maximum growth is found about 

 the eighth to ninth day, after which disintegration sets in, resulting 

 in total disappearance about the fifteenth day. Subcultures are 

 best made from the fourth to the ninth day, but after that date 



