624 JOHN E. MUBLDT 



The energy production expressed in absolute figures in both cases 1 and 

 3 is the same after as before parturition. In case 2 there was an increase 

 of about .7 per cent in the postpartum over the antepartum metabolism. 

 This can be accounted for by the fact that the child cried lustily at times 

 on two out of three postpartum days and the crying disturbed the mother. 

 One is justified, therefore, in the conclusion that the total metabolism of 

 mother and child immediately after birth of the child is not greater in 

 absolute amount than it was immediately before delivery. The extra 

 metabolism of pregnancy, at its culmination, due in -part to the activity 

 of the accessory maternal structures as well as to the fetus, as in the dog, 

 is just compensated by an extra metabolism set up in the new-born as it 

 begins an independent existence. ^^Since the mammalian embryo has no 

 appreciable weight as compared with the mother until near the middle of 

 the gestation period, it is easily understood why several workers (Magnus- 

 Levy) using the Zuntz method failed to find any increase in the oxygen con- 

 sumption per unit of weight in pregnant as contrasted with non-pregnant 

 women; or if such an increase appeared at all, it became evident only com- 

 paratively late in the gestation periodf] This- was confirmed with respect 

 to the total energy production as computed from the output of nitrogen and 

 carbon by the writer in a series of experiments on a pregnant dog. The 

 only exception to the rule is a single case reported by Magnus-Levy in which 

 he observed both an absolute and a relative increase in oxygen absorption as 

 early as the third month of gestation. 



Leo Zuntz (6) reported three cases on two of which he made observations 

 by means of the Zuntz-Geppert method throughout the gestation period 

 and on the third a few observations in the sixth month only. He com- 

 pared the results with figures previously obtained from the same subject 

 in sexual rest. The first two increased considerably in weight during 

 the gestation period, quite independently of the product of conception, 

 so that the amount of oxygen absorbed, when expressed per kilogram of 

 body weight, was even less in the ninth month (Case C) than it had been 

 in sexual rest, or was so little greater (Case B) that Zuntz believed the 

 difference was entirely due to the increased labor of respiration. In the 

 third case, however, the weight was less in the sixth month than it had 

 been previous to conception, the oxygen absorption being as a consequence 

 significantly larger per unit of weight in the pregnant condition. On 

 the basis of this experiment and that of Magnus-Levy, Zuntz concluded 

 that at the end of pregnancy the respiratory metabolism normally would 

 be considerably higher than in sexual rest and that this is not altogether 

 due to increased labor of respiration. Carpenter arid Murlm compared 

 their determinations on three normal cases of pregnancy with basal de- 

 terminations on seven normal, non-pregnant women ranging in age from 

 18 to 55 years and in weight from 37 to 66 kilograms. Table 24 presents 

 a comparison of the energy metabolism in the ninth month of pregnancy 



