GL YCOGENE$IS~- THEOR Y OF BERNARD. 923 



the body, gives off such material into the blood in the form of dextrose. 

 This dextrose is taken to the tissues and is used by them, becoming 

 oxidised within them. Whether this oxidation occurs outside the actual 

 bioplasm, or whether the dextrose which is taken to the bioplasm 

 becomes first of all built up into its molecules and then split up 

 and oxidised, and whether .the products of its oxidation leave the 

 muscles in their ultimate forms, are questions which we need not 

 now consider. In either case the effect of such oxidation is to produce 

 energy (in the form of heat and mechanical work). 



This view of Bernard's has, on the whole, met with general favour among 

 physiologists. Some there are, indeed, who have so far proceeded beyond 

 Bernard, as to assert that the wJtole energy of the body is derived from the 

 oxidation of carbohydrate. Such carbohydrate, which is taken to the tissues 

 in the blood in the form of glucose, is assumed to be formed either from the 

 stored carbohydrate of the liver, as Bernard supposed, or independently of this 

 from proteid, or even from fatty materials in the liver cells, and being carried 

 to the tissues to be taken up by them, oxidised within them, and thus become 

 the immediate source of the energy of the body, whether this takes the 

 form of heat or work. It is in fact assumed that the main result of 

 metabolism within the body is the production in one part, and the destruction 

 in another, of carbohydrate. Such a view has been chiefly contended for by 

 Seegen l and Chauveau, who hold that even the proteid material of the food, 

 at least its non-nitrogenous part, must ultimately become converted into 

 carbohydrate before it can become oxidised in the tissues (see p. 914). 



It is obvious that Bernard's theory is, in the main, dependent upon the 

 circumstance that sugar is continually being passed from the liver into the 

 hepatic blood, even during starvation, and this, in fact, has been directly 

 affirmed by Bernard and others. Even in the fasting animal, sugar is found in 

 the blood, except at the extreme end of an inanition period ; and, according to 

 the analyses of Seegen, it always occurs in larger amount in the hepatic blood, 

 whatever be the nature of the food, whether proteid, fat, or carbohydrate, 

 than in blood from any other source. This occurrence of dextrose in 

 larger proportion in the hepatic blood than in the rest of the blood of the 

 body, if it were completely and satisfactorily determined, would be a fact of 

 fundamental importance, and would go very far to establish Bernard's theory 

 upon a firm basis. But there are reasons for believing that such an excess of 

 sugar as has been found by Seegen and other observers is not present 

 under absolutely normal conditions. Seegen's experiments were made without 

 anaesthetics, and it is a well-established fact that any operation upon an 

 animal, which involves the production of pain, will immediately produce 

 a transformation of the glycogen of the liver into sugar, and the appearance of 

 an excess of sugar in the hepatic blood. 2 It is, in fact, admitted by Seegen 



1 "Die Zuckerbildung im Thierkbrper," Berlin, 1890, S. 218, and numerous papers in 

 the Arch.f. d. yes. Physiol., Bonn, and in the Ccntralbl. f. Physiol., Leipzig u. Wien. 



2 Seegen calculates that in man from 500 to 1000 grms. of dextrose may pass into 

 the blood from the liver in twenty-four hours. But since his calculations are based upon 

 experiments made upon animals in an abnoimal condition so far as the carbohydrate 

 metabolism is concerned, these numbers cannot be accepted. Cf. Abeles, Med. Jahrb., 

 Wien, 1886, S. 383; I. Munk, Berl. Tclin. Wchnschr., 1890, S. 595; also Pfluger, 

 Arch. f. d. ges. Physiol. , Bonn, 1891, Bd. 1. S. 330, 396 ; Mosse, ibid., 1896, Bd. Ixiii. S. 

 613 ; 'L\mtz* Centralbl. f. Physiol., Leipzig u. Wien, 1896, S. 561. The blood is obtained 

 either directly from one of the hepatic veins, or by passing a catheter up into the inferior 

 cava, this vein being then blocked just below the reception of the hepatic veins by the 

 inflation of an india-rubber bag ; or a tube is passed down from the jugular vein through 

 the right auricle into the inferior cava, and its bent end is made to enter one of the 

 hepatic veins. 



