The study of experimental conditions of low blood-pressure has been limited for the most part to conditions of shock due to traumatism, thermic influences, or exposure, and aside from pharmacological investigations of the mode of action of certain substances such as arsenic, but few attempts to study, experimentally, low blood-pressure due to toxic agents have been made. The study of the latter should, therefore, be of interest not only to the internist, in that it may offer an explanation of conditions of collapse or shock occurring in medical as controlled with surgical practice, but also of general importance, in that it supplements the experimental work of Crile1 and others on surgical shock. Such a study was suggested by the observation of Biedl and Kraus,2 which we3 have confirmed, that anaphylactic shock in the dog is characterized by a low blood-pressure resembling in many ways that of