On the morphological variability of Obermeier's spirochetes

Having at present a large number of observations on the variability of morphological characters of Obermeier's spirochaetes in cultures, we intend in the present report to point out a number of facts which seem to us to be of general interest. The following material was obtained by culturing a number of strains of spirochaetes of recurrent typhus for several years; it also includes observations obtained by artificial infection of humans with our cultures made for therapeutic purposes on paralytic patients (in the clinic of Prof. T.I. Yudin) and syphilitic patients (in the venereological department of the Institute for Advanced Medical Training in Kazan, Prof. M.S. Pilnov).