224 THE PROTOZOA 



granules but no spirochaetes has brought about spirochaete infection in mice. He 

 considers that infection probably occurs through material voided from the Mal- 

 pighian tubes rather than through the medium of veneno-salivary secretions. 



Other spirochaetes that have been considered as pathogenic for the type of re- 

 lapsing fever in India and that of America are the S. carteri and the S. novyi. 



Nicolle has shown with relapsing fever of Algiers that the body louse can trans- 

 mit the infection by spirochaete containing material from the crushed louse being 

 rubbed into the wound made by the louse in biting. Eggs from an infected louse 

 hatch out infected young lice, thus showing the hereditary transmission. It is 

 now also considered that infection with South African relapsing fever by O. moubata 

 occurs by the rubbing in of spirochaete containing faeces into the wound made by 

 the bite of the tick. These, as with plague infection from the contaminated faeces 

 of the rat flea, are instances of the contamination mode of infection. Noguchi has 

 recently cultivated the various species of pathogenic human spirochaetes by employ- 

 ing a method similar to that used in cultivating the organism of syphilis. He noted 

 longitudinal division in his cultures. 



S. vincenti. This is a very delicate spiral-shaped organism which has been found 

 in conjunction with a fusiform bacillus in a throat inflammation, usually termed 

 Vincent's angina. , 



S. refringens. This Spirochaeta is frequently associated with the Treponema 

 pallidum and is common in genital ulcerations. It is thicker, has less regular and 

 more flattened curves and stains more readily. By "dark ground illumination" it 

 is thicker, of a yellow tint instead of pure white, and moves in its entire length. 



Treponema. 



The genus Treponema has no undulating membrane and has a 

 flagellum at each end. 



Treponema pallidum (Spirochaeta pallida). -This is the cause of 

 syphilis. It is characterized by the very geometric regularity of the 

 spirals, which are deeply cut, and in focusing up and down continue in 

 focus (like a corkscrew). They require about thirty minutes to stain 

 distinctly with Giemsa's stain and the attenuated ends or flagella should 

 always be noted before reporting their presence. 



Treponemata are found in the cellular areas surrounding the thickened blood- 

 vessels and in the coats of the larger arteries. To stain them in section Levaditi's 

 method is the best. 



The India-ink method of Burri is highly recommended. Take one loopful of 

 secretion from a chancre and deposit it on one end of a slide. Surround this drop 

 with five loopfuls of distilled water and five loopfuls of Giinther and Wagner's ink. 

 Mix and make a smear as for blood. When dry examine with the oil immersion 

 objective and the treponemata will be found to stand out as white spirals against 

 a dark background. Treponemata often appear as if bent in the middle. 



Harrison prefers collargol to India-ink. One part of collargol is put in a bottle 

 with 19 parts of water and well shaken. This shaking is repeated. One loopful 



