1. A mucin-producing spirochoeta has been obtained in pure culture from a case of pyorrhea alveolaris. This organism is an independent species of the genus Treponema and, as it is recognized for the first time, I propose for it the name Treponema mucosum. 2. Morphologically the mucosum is difficult to separate from the pallidum and microdentium, but, through its biological properties and animal...