32 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



theless the oxygen consumption and carbon-dioxide production were 

 much lower per kilogram of body-weight than they were under pre-war 

 conditions. The nitrogen excretion per day for Zuntz was relatively 

 small, averaging not far from 6.50 grams. He computes that he was 

 consuming approximately 51 to 52 grams of protein per day. Calcu- 

 lating the calories per square meter on the basis of the Meeh formula, 

 he finds a reduction in heat production per square meter of body-surface 

 corresponding to 7.3 per cent. 



With Loewy the loss in body-weight was not so great as with Zuntz. 

 The oxygen consumption per kilogram of body-weight and per square 

 meter of body-surface was considerably reduced, being 12.2 per cent 

 lower per kilogram of body- weight than formerly. Unlike Zuntz, 

 Loewy lived upon a reasonably liberal nitrogen intake, since the nitro- 

 gen in the urine averaged 13.95 grams per day. Taking into con- 

 sideration the nitrogen in the feces, it is computed that the nitrogen 

 content of the food was the equivalent of 97.6 grams protein, or nearly 

 twice that of Zuntz. 



As an explanation of this lowering of metabolism, the authors suggest 

 two possibilities: one, that there was a greatly reduced protein intake; 

 the other, that with the loss of body-weight there was an even greater 

 percentage loss of active cell substance. They conclude that the first of 

 these suppositions is disproved by the results obtained with Loewy, who 

 partook of a fairly liberal nitrogen diet. They finally conclude that 

 the main cause of the reduction is the loss of active cell substance and, 

 further, that even if there is a fairly liberal protein intake in the diet, 

 insufficient calories will cause a great loss of active body substance. 



Observations of the pulse-rate with Zuntz indicate a slight falling off 

 in the 1916 series of experiments. During this series hemoglobin 

 determinations were made and showed that the blood of both men indi- 

 cated 110 per cent of hemoglobin on the Plesch hemoglobinometer. 



It is thus clear that these two German scientists have definitely shown 

 in their own cases measurably lowered metabolism as a result of the loss 

 in weight incidental to the restricted diet of war times. In our exami- 

 nation of the earlier hterature nowhere do we find such clear-cut state- 

 ments with experimental evidence of the possibility of lowering the 

 basal metabolism of man as are seen in these experiments of Loewy 

 and Zuntz. The conflicting evidence noted throughout the litera- 

 ture for animals and for pathological cases with man is entirely absent 

 in these two series of experiments. 



Jansen, 1917. — The details of a second war-diet study, which was 

 made by Jansen^ and confirmed the findings of Loewy and Zuntz, 

 came to our attention only when the report of our research had reached 

 the first galley proof and hence too late for extended analysis. With 

 13 subjects Jansen studied the influence of a low-calorie diet upon the 



1 Jansen, Deutsch. Arch. f. klin. Med., 1917, 124, p. 1. 



