The work of previous investigators was confirmed in that the microorganism of rat-bite fever was found to have flagella which are clearly visible by dark-field illumination and which can be stained. The best staining is obtained with alkalinized Akashi solution, which is a modification of Giemsa's solution; the vapor of osmic acid gives the best fixation.
The number of demonstrable flagella seems to vary with the technique. Sometimes many slender flagella unite into one large one or one large flagellum divides into several smaller ones. It may be concluded that commonly many slender flagella occur at the ends and that these may unite into one or several large flagella. In the living microorganism the flagella appear to be spiral. Their form in fixed preparations depends upon the method employed. Some long forms have flagella arising at the middle of the body; this seems to indicate that division is transverse and not longitudinal as generally believed. The rigid body, the signs of transverse division, and multiple flagella seem to distinguish the forms reported here from spirochetes and indicate that they are spirilla.