36 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



an excess of carbon dioxide produced in the transformation of the excess 

 carbohydrate into fat; and third, the actual increment in the carbon- 

 dioxide production due to an increased total metabolism. Although 

 Johansson did not take into account all of these three factors, certain 

 of his conclusions are important. 



An increment in the carbon-dioxide production was found with all 

 sugars, this being greatest with levulose and sucrose and least with 

 dextrose. For each sugar the maximum increase was obtained with 

 about 150 grams; the length of the increase never exceeded 6 hours, 

 which corresponds to the time required for the passing of food through 

 the small intestine. Levulose gave twice as great an increase in the 

 carbon-dioxide excretion as did the same amount of dextrose. Johans- 

 son contends that the increase in carbon dioxide after the inges- 

 tion of sugar can not be satisfactorily explained on the assumption 

 of a Verdauungsarbeit. The maximum capacity of the intestine for 

 absorbing sugar averages about 80 grams per hour. The maximum 

 carbon-dioxide output following the feeding of cane sugar and levulose 

 was about 35 grams per hour, with a basal value of 22 grams. With 

 dextrose and milk sugar the increment was only about one-half that 

 with the other sugars. A series of experiments in which sugars were 

 given with varying amounts of water led Johansson to the conclusion 

 that the ingestion of water played no role in the metabolism, since the 

 increase in carbon dioxide was entirely independent of the amount of 

 water consumed. 



Staehelin, 1908. In a series of observations on an obese individual, 

 Staehelin, 1 using the Zuntz method for determining the oxygen con- 

 sumption and carbon-dioxide production, found that the increment 

 after eating meat was very much less than that found with normal 

 individuals. He reports 3 experiments niichtern, 2 experiments with 

 a meat diet, 2 with a diet of cabbage, potatoes, and apples, and 2 with 

 bacon, bread, and butter. Staehelin concludes that the vegetable diet, 

 because of the increased work of digestion, results in an increase in the 

 oxygen consumption, while a cellulose-poor diet (fat diet) has no notice- 

 able effect. He concludes that the Verdauungsarbeit may be likewise 

 recognized with obese individuals. 



The oxygen consumption after food was determined by Staehelin 2 

 with the chamber method in 5 experiments on himself and 2 on tuber- 

 cular patients. These experiments, made with the Jaquet respiration 

 chamber in the Basel clinic, are of particular interest, since Staehelin 

 attempted to minimize muscular activity and to secure uniformity in 

 conditions by carrying out experiments in the night, when the subject 

 slept for a greater part of the time. The importance of securing 

 observations with the subject asleep and in complete muscular repose 



'Staehelin, Zeitsohr. f. klin. Med., 190H, 65, p. 425. 2 /Wd., 66, p. 201. 



