As long ago as 1873, Obermeier discovered that a
flexible spiral organism, about o.i JJL in diameter and
from 20-40 IJL in length, could be observed in the blood
of patients suffering from relapsing fever.
Although many of the best bacteriologists of our day
have occupied themselves with the study of this spiril-
lum, we really have, at present, very little more know-
ledge than that given us by Obermeier.
FIG. 120.—Spirochseta febris recurrentis; x 650 (Heim).
The spirilla (Fig. 120) are generally very numerous,
are long, slender, and flexible (spirochseta), and possess
a vigorous movement by flagella. The ends are rather
The spirillum stains well by ordinary methods, but
not by Gram's method. It seems to be a strict parasite,
and has never been cultivated artificially.
Of the pathogenesis of the organism there can be 110
doubt, as it is invariably present in relapsing fever and