A new quantitative method of testing the sense of smell has recently been described.1 Whereas by all former methods odors were carried to the olfactory membrane through inhalation or sniffing, by this new method the odorous substance is injected by a process called "blast injection" into one or both nasal passages during cessation of breathing. The known force of the injection takes the place of the inspiratory movement. In this test the volume of air and odor and the pressure of the injection can be measured. "By this test it has become possible to study the threshold of olfactory sensibility, to determine fixed values (olfactory coefficients) for each odor and to gain considerable information regarding the relative importance of the volume and pressure of the olfactory stimulus."2 The originators of this method have made practical use of it in the localization of supratentorial tumors of the brain. They