Among the poisonous plants growing in temperate regions and known to civilized man,Cicuta, or water hemlock, is characterized by a highly pronounced toxicity. Its deleterious effects on the human system are well known, owing to the fact that it is found in nearly all parts of the United States. It is of general interest because poisoning directly traceable to this plant has caused many deaths among men and animals. Recently, in the city of New Haven, a series of cases of acute poisoning occurred simultaneously and from the same source. The resulting investigation which determined the cause to beCicutaprompts me to report these cases briefly, so as to direct attention to the existence of this plant. Cicutahas been definitely recognized in the United States since the middle of the sixteenth century. Prior to this time, it was confused withConiumand, as it could not be