3 7 6 
The genus Treponema has a spiral body, not 
flattened, cylindrical in section, flagellum at each end. 
No undulating membrane, e.g., T. pallidum of syphilis 
and T, pertenue of yaws. 
i. Sp. recurrentis. —The cause of relapsing fever in 
Europe. It remains to be seen whether the spiro- 
chaetes of relapsing fever elsewhere are identical with 
this or not. 
Symptoms. —The attack lasts, as a rule, about six 
to seven days. The apyretic interval five to ten days. 
The following attack is shorter and the apyrexia longer. 
In two-thirds of the cases there may be a third attack, 
and even five or six relapses occur (cp. S. duttoni). 
Fig. 115. ('Upper figure ) Plan of a spirochaete ; 
(Lower figure) Plan of a treponeme (after Schaudinn) 
Blood Examination. —Examine during the pyrexia 
a fresh film with a 1/6 lens. Note the slight dis¬ 
turbance among the corpuscles and, when attentively 
focussed, the gliding undulating movement of the 
parasite. If not found fresh, make a thick smear of 
blood on a slide as big as the area of a sixpenny bit. 
Dry thoroughly. Do not fix. Stain with gentian 
violet (a few drops of a saturated alcoholic solution to 
a teaspoonful of water) for about five minutes or less, or 
with Romanowsky. Parasites are generally numerous 
during the pyrexia, but disappear completely during 
the apyretic interval. 
