It is generally recognized that the present classification of bacterial dysenteries as well as of the dysentery bacilli is in a somewhat unsatisfactory position. I venture therefore to bring forward again a classification I suggested some years ago, which so far has attracted very little attention. This classification to a great extent was followed by Chalmers and myself in the third edition of our Manual of Tropical Medicine. According to this classification bacterial dysenteries are separated into three groups: 1. Bacterial dysentery, sensu stricto (synonyms Shigadysentery, Shiga-Kruse dysentery), due to dysentery organisms which do not ferment lactose or mannitol and do not clot milk (Shiga-Kruse bacillus). 2. Paradysentery, due to organisms which do not ferment lactose, ferment mannitol (acid only), do not clot milk (Flexner, Hiss-Russell, etc.). 3. Metadysentery, due to organisms which, as is the case with the true dysentery bacilli, do not produce gas in any sugar, but either ferment lactose (acid only) and clot milk, or ferment lactose (acid only) without clotting milk, or clot milk without fermenting lactose (organisms of the genus Dysenteroides and Lankoides).