Elaborate studies of the effect of foodstuffs on the respiratory metabolism have been made by Rubner1 and Lusk,2 who are the principal workers in this field. Reference should be made to the latter for an excellent review of the subject. These investigations were concerned chiefly with the calorimetric observations, in which the magnitude of pulmonary ventilation was not measured.
In a previous communication3 the effect of protein ingestion on the heat production of two tuberculous patients and two normal subjects was found to be identical. On a priori grounds the assumption was made that the pulmonary ventilation varies directly with the metabolism. Confirmatory evidence on this point is given by Peabody4 who shows the parallelism between the minute volume of air expired and the level of metabolism in patients with exophthalmic goiter. The general validity of the assumption is well demonstrated by Pearce,5 who showed that total ventilation and cardiac