SPECIFIC DYNAMIC ACTION. 931 



On partaking of large amounts of food, especially proteins, by car- 

 nivora, the digestion work in the above sense is not sufficient to account 

 for the increase in metabolism, and in these cases, besides this, we must 

 accept an increase in the chemical transformation process in the animal 

 body brought on by the foodstuffs in an unknown manner (specific 

 dynamic action of foodstuffs, according to RUBNER). The only real 

 difference in opinion between the various experimenters consists, so far 

 as HAMMARSTEN can see, in that according to the ZUNTZ school, normally 

 on supplying sufficient food it is the digestion work in the above sense 

 which chiefly causes the rise in metabolism after taking food, while 

 according to the views of VOIT-RUBNER, with which HEILNER agrees, 

 it is on the contrary the specific dynamic action. 



That the proteins or their cleavage products, without regard to the 

 digestion work, cause a rise in the metabolism seems to be generally 

 accepted. This rise, according to GIGON, is not proportional to the 

 protein supply, as on supplying quantities of protein represented by 

 1: 2: 4: 3 the oxygen absorption was in the proportion 1:3:6:9 and the 

 carbon dioxide elimination was in the proportion 1:4:8:12. On the 

 introduction of glucose GIGON found, as first shown by JOHANSSON/ 

 that the introduction of carbohydrate caused a proportional rise in the 

 carbon dioxide elimination to a maximal limit of 150 grams. The 

 conditions on supplying fat are harder to judge, but GIGON found no rise 

 in metabolism on introducing oil. 



The rise in the gas exchange occurring after feeding protein and sugar 

 is added, according to GIGON, entirely to the basal metabolism. A 

 substitution in the basal metabolism of the catabolized body constituents 

 by the food taken does not take place according to GIGON and, as example, 

 the protein is not replaced from catabolism by the sugar introduced. 

 The isodynamic law does not apply to the metabolism occurring the 

 first few hours after supplying food, as shown by JOHANSSON and HELL- 

 GREN, and GIGON 2 believes that the foodstuffs first pass into the various 

 depots of the body to be later used for purposes of energy. Proteins 

 serve only to a slight degree to replace the catabolized body protein; 

 the remainder is stored up in part as glycogen and in part as fat. The 

 fat is deposited as such and the carbohydrates are deposited as glycogen 

 and fat. 



As the three foodstuffs influence the metabolism in very different ways we 

 can, according to GIGON, speak of a specific action of the foodstuffs. This 

 action, according to him, is more of a material than of a dynamic kind, and the 

 expression, specific dynamic action, may lead to an erroneous conception. 



1 Skand. Arch, f . Physiol., 21. 



2 Johansson with Hellgren, Hammarsten's Festschrift, 1906; Gigon, Skand. Arch. f. 

 Physiol., 21. 



