THE communication from Prof. Wilson Baker and his collaborator1 prompts us to intimate that we also have concerned ourselves with the sydnones, but from the point of view that their formation might be related to the racemization of ñ-acetylaminocarboxylic acids by acetic anhydride. Bergmann and Zervas2 adduced evidence that this change depended on enolization of the anhydro-compound to I.