600 A MANUAL OF BACTERIOLOGY 



dealing with a double infection of both a trypanosome and a 

 Halteridium, not that one was transformed into the other. 



Spirochaeta recurrentis (Obermeieri). Found in the 

 blood-plasma, not in the corpuscles, in relapsing fever 

 during the febrile paroxysms. It is very slender and 

 delicate, measuring 12 to 16 \L in length, and actively 

 motile (Plate XXIV, 6). Bugs were formerly supposed 

 to transmit this parasite, but Nicolle, Blaizot and Conseil 

 have established the body louse as the agent of trans- 

 mission. Infection is, however, not due to the bite of the 

 louse, but to lice being crushed by the victim's scratching 

 and the contents of the lice rubbed into the abrasions. 

 The lice not only retain the infection for the rest of their 

 lives, but the spirochaetes pass into their eggs, and these 

 eggs and the larvae hatched from them may similarly be 

 infective to man. It is inoculable into monkeys, and 

 less readily into rats. 



Noguchi and Hata l have cultivated this form : the 

 latter in a medium consisting of one part of horse-serum 

 and two parts of saline. This mixture is placed in tubes 

 to a depth of 7 cm., which are then heated slowly in a 

 water-bath from 58 to 70 C., at which they are kept 

 for thirty minutes. Small pieces of rabbit kidney are then 

 pushed to the bottom of the tubes, and the incubation 

 must be carried out anaerobically. 



It is probable that the spirochaetes of relapsing fever 

 in different countries are distinct species. 



Spirochaeta Dutioni. Found in the blood-plasma in 

 African relapsing, or tick, fever. It closely resembles 

 the S. recurrentis, but is more readily inoculable into 

 rats, mice, and guinea-pigs, and the one does not protect 

 against the other. It is conveyed by a tick, Ormthodoros 

 moubata, the Malpighian secretion of which is the prin- 

 cipal infective agent. The eggs of infected ticks are also 



1 Centr. f. Bakt., Abt. I (Originale), vol. Ixxii, 1913, p. 107. 



