PRODUCTION OF SrGAK IX THE LIVER. 307 



him to seize the portal vein as it enters at the transverse 

 fissure, and apply a ligature. The abdomen was then freely 

 opened and a ligature applied to the vena cava just above the 

 renal veins, to shut off the blood from the posterior extremi- 

 ties. The chest was then opened, and a ligature was applied 

 to the vena cava just above the opening of the hepatic veins. 

 Operating in this way, blood may be taken from the portal 

 system before it enters the liver, and from the hepatic veins 

 as it passes out. In the blood from the portal system no 

 sugar is to be found, but its presence is unmistakable in the 

 blood from the hepatic veins. 1 To avoid disturbing the cir- 

 culation in the liver, and in order to collect from the hepatic 

 veins as large a quantity of blood as possible, Bernard modi- 

 fied the experiment, in some instances, by introducing into 

 the vena cava in the abdomen a double sound, the extremity 

 of which is provided with a bulb of India-rubber. This was 

 pushed into the vein above the diaphragm ; and by inflating 

 the bulb, the vein was obstructed above the liver, and the 

 blood could be collected through one of the canulse, as it 

 came directly from the hepatic vessels. Bernard never 

 failed to determine the presence of sugar in these specimens 

 of blood, employing a number of different processes, includ- 

 ing the fermentation-test and even collecting the alcohol. 8 

 To complete the proof of the existence of sugar in the blood 

 coming from the liver, Bernard demonstrated its presence in 

 blood taken from the right auricle in a living animal. He 



O O 



also showed that during digestion the whole mass of blood 

 contained sugar, but the quantity was greater in the right 

 side of the heart than in the arterial system. 8 



It is unnecessary to cite all the authorities that have 

 confirmed the observations of Bernard. Shortly after these 



1 BERNARD, Recherches sur une nouvdle fondwn du foie, Paris, 1853, p. 56. 



2 BERNARD, Lemons de physiologic experimentale, Paris, 1855, p. 494. The 

 reader will find here a description, with a figure, of the instrument mentioned 

 in the text, which is very ingenious. 



3 Op. tit., p. 120. 



