In addition to the records of the respiration rate obtained in the experiments with the respiratory-valve apparatus, data regarding the total ventilation of the lungs per minute were also secured. From these two a computation could be made of the volume per respiration. "Using the respiratory exchange, particularly the carbondioxide output, one can, assuming a dead space, also compute the carbon-dioxide tension in the alveolar air. In addition to these data we determined directly in a large number of cases the alveolar carbon-dioxide tension by a special technique. (See p. 79.) All of these values are recorded, together with certain other respiratory figures, in table 111.

The data for the total ventilation of the lungs per minute are recorded in the first two columns of the table, the first column giving the ventilation as actually observed from readings of the spirometer, and the second, the same data reduced to 0° C. and 760 mm. pressure.

The actual number of observations made of the total ventilation of the lungs prior to the reduction in diet are very few, only Can and Gar showing more than one value. The data for October 5 or subsequent thereto were obtained after the reduction in diet began. An inspection of the figures in both columns a and b shows a distinct tendency for the total ventilation of the lungs, both observed and reduced, to decrease somewhat with the length of time, although not necessarily in direct proportion to it. As a matter of fact, for the most part high values were found only in the first three observations, and but occasionally thereafter. In nearly every case after the first two weeks in October, a high ventilation of the lungs was accompanied by a large oxygen consumption. For example, with Gar, after a long series of values for ventilation per minute of 4.5 liters or under (see second column), we find on January 10, 14, and 18 three high values of practically 5 liters or over. These were all accompanied by a distinct increase in the oxygen consumption. The total metabolism is thus actually increased and there is an increased ventilation of the lungs to bring away the excess formation of the carbon dioxide. In general, there is a clear tendency for a decrease in the total ventilation of the lungs with a reduction in diet.