THE DEEPENING OF PHYSIOLOGY. 293 



(2) Recognition of Greater Complexity of Func- 

 tion. In the early years of the nineteenth century 

 physicians were wont to say that the liver was an 

 organ whose function consisted in secreting bile. 

 In other words, a very obvious function of a big organ 

 had been seized upon, and the demonstrable certainty 

 of it served rather to hinder than to promote further 

 research. That the liver does secrete bile is plain 

 enough, but the detection of this function did not 

 even hint at the real importance of the organ in ques- 

 tion. 



The transition towards a recognition of the more 

 complex and manifold functions of this the largest 

 gland in the body may be associated with the work 

 of Claude Bernard (1813-1878) who demonstrated 

 its " glycogenic function." He showed (1857) that 

 after a meal the liver acts upon the food-laden blood, 

 and forms glycogen or animal starch, C 12 , H 20 , O 10 , 

 H 2 O, and thereafter allows this store to pass away 

 gradually, probably in the form of a soluble sugar, in 

 the blood, to serve as a food for the tissues, the 

 muscles in particular. The carbohydrates digested 

 in the food-canal enter the blood as sugars, assuming 

 the form of dextrose, and while the amount of this in 

 the general blood is about 0.1 per cent., it reaches 

 0.2-0.3 per cent, in the (hepatic-portal) veins leading 

 from the gut to the liver after a meal rich in starch. 

 After abundant carbohydrate food the glycogeu-store 

 in the liver may become enormous, amounting to 

 even 12 per cent, in the fowl. 



But the glycogenic function which Claude Bernard 

 disclosed is only a second out of the many functions 

 of the liver. Interposed as it is, a great living 

 sponge, in the current of blood that bears soluble 

 material from the food-canal to the heart, it has the 



