Taxonomical Studies on the Spirochetes : Part I. Introduction and Historical Reviews

A research history on the taxonomy of the spirochetes was reviewed and evaluated from the literatures in the present paper. Particularly, three main problems were discussed. They are the place of the spirochetes in the microbial world, the protozoa or the protophyta, some comparisons between the spirochetes and the resembling bacteria, and the classification of the order Spirochaetales. The author concluded that the fundamental morphological features of the spirochetal cell under electron microscopy must be re-considered.