PREVIOUS INVESTIGATIONS. 29 



they were 33, 23, 12, and 6 per cent for the first 4 hours, followed by 

 slightly negative values for the remainder of the night. The average 

 increment for the 14 hours from the first hour after breakfast until the 

 fourth hour after the evening meal is computed as 21 per cent. The 

 author points out that the true metabolism is really somewhat greater, 

 since the mechanical work of chewing and swallowing is not noted 

 in the experiments. An interesting computation is made of the total 

 increment for the entire day, which is computed to amount to 13 per 

 cent for the oxygen consumption and 19.75 per cent for the carbon- 

 dioxide production. 



This article, which is justly cited as a classic, represents by far one 

 of the most critical and ambitious attempts to solve the perplexing 

 problem of the influence of the ingestion of food upon the metabolism 

 of human subjects. The observations on men are substantiated by 

 even more extensive series of observations on dogs. The dominant 

 note of the discussion is that the increase following the ingestion of 

 food is in large part due to the work of digestion in contradistinction 

 to the explanation of it by Rubner's theory of specific dynamic action. 

 On the other hand, Magnus-Levy's discussion of the subject has the 

 great advantage of giving a concrete statement as to the probable 

 cause for the increased metabolism and consequently is more subject 

 to direct experimental attack than is the more subtle explanation offered 

 by the specific dynamic action theory, which in itself has undergone 

 marked revision in recent years. 



Sondenand Tigerstedt, 1895. The extensive research carried out by 

 Sonden and Tigerstedt 1 with the large respiration chamber in the 

 Karolinska Institute in Stockholm does not lend itself particularly well 

 to a discussion of the influence of the ingestion of food, inasmuch as in 

 practically all of the experiments the subjects indulged in more or 

 less muscular activity, and in relatively few cases were there controlled 

 periods of fasting; furthermore, only the carbon-dioxide production was 

 determined. As a result of the comparison of the data obtained in the 

 evening experiments and experiments on the following morning, the 

 authors concluded that the carbon-dioxide production in the morning 

 experiments was about 14 per cent lower than that in the evening 

 experiments. 



Falloise and Dubois, 1896. Falloise and Dubois, 2 collecting expired 

 air in a rubber bag and analyzing the air by the Hempel method, made 

 a number of fasting experiments 15 hours after food and obtained an 

 average respiratory quotient of 0.71. In the food experiments, a mixed 

 diet was first given and the respiratory quotient was studied every 

 half hour for 3 hours after the meal. With this diet the respiratory 



and Tigerstedt, Skand. Arch. f. Physiol., 1895, 6, p. 1. 

 "Falloise and Dubois, Travaux du Lab. de L. Fredericq, 1893-95, 5, p. 147; Arch, de Biol., 

 1896, 14, p. 457. 



