494 A MANUAL OF BACTERIOLOGY 



owl minute slender trypanosomes occur ; these later penetrate 

 leucocytes, and develop into relatively very large trypanosome 

 forms (which have been termed Leucocytozoa). These intra- 

 oorpuscular forms are male and female gametocytes, the male being 

 smaller and more slender than the female. If taken into the gnat's 

 stomach, the male gametocytes give rise to eight microgametes by 

 a process of sporulation, which fertilise the macrogamete, and the 

 resulting zygote ultimately forms by sporulation an immense 

 number of spirochaetes. 



In the case of a Halteridium parasite of the little owl (Athene 

 noctua), Schaudinn claimed to have shown that it is a stage of a 

 trypanosome (jP. noctuce) which is disseminated by the common gnat. 

 His observations have not been confirmed, and Novy and McNeal 

 believe that Schaudinn was 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 //. in length, and actively 

 motile (Plate XXI. 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 C. to 70 C., at which they are kept 



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



