A systematic investigation into the physiological action of ozone, so far as we are aware, has never been undertaken. Isolated observations have been made by many while engaged in the examination of its physical and chemical properties, which have chiefly tended to show that it acts as an irritant on the mucous membrane of the respiratory tract, and they have also observed the peculiar odour which it excites by its effect on the organ of smell, from which the name ozone originated. Beyond this little has been attempted.