THE PANCREAS 965 



vein. On reaching the liver, some of the glucose, levulose, and galac- 

 tose is taken up by the hepatic cells, and is deposited here in the form 

 of a colloidal polysaccharidcj known as glycogen. Consequently, one 

 of the functions of this organ is to store and to hold in reserve a certain 

 surplus amount of carbohydrate material until needed by the other 

 tissues. But, since the muscles contain almost as much glycogen 

 as the liver, the latter cannot be said to be the only place in which 

 this substance is deposited. At all events, the liver is constantly 

 called upon to release some of this glycogen and more particularly 

 during the periods intervening between meals, when practically no 

 sugar is absorbed. Lastly, this organ possesses the power of forming 

 dextrose from protein material and even from many partially oxidized 

 products of other tissues. This synthesis of glycogen, as well as the 

 reconversion of this substance into sugar, must be effected by means 

 of a special intrahepatic principle. Consequently, it may be said 

 that this organ furnishes an internal secretory product which has to 

 do with the metabolism of the carbohydrates. 



D. THE PANCREAS 



The Removal of the Pancreas. — Inasmuch as the general phy- 

 siological anatomy of the pancreas has been discussed at some length 

 in connection with its external secretion, it may suffice at this time to 

 state that this organ also contains numerous colonies of cells which have 

 been named, after their discoverer, the islands of Langerhans (1869). 

 These groups of cells are tugged away in between the different acini 

 and are composed of polygonal cells possessing poorly defined bound- 

 aries, large round nuclei, and relatively few and small granules. They 

 are copiously supphed with blood from an interstitial system of cap- 

 illaries. Bensley^ has proved by the method of intravitam staining 

 that these structures are permanent and should not be regarded as 

 developing reserve cells of the acini. 



It was CI. Bernard^ who first called attention to the fact that the 

 occlusion of the duct of Wirsung produces a complete atrophy of the 

 acini of the pancreas, but does not destroy the islets of Langerhans. 

 In 1889, Mering and Minkowski^ proved that the total extirpation 

 of this organ gives rise not only to digestive disorders, owing to the 

 loss of the pancreatic juice, but also to a complex of symptoms com- 

 monly associated with the disease, called diabetes mellitus. The 

 animal shows a hyperglycemia, glycosuria, polyuria, poliphagia, a 

 loss of weight, an abnormal thirst and hunger, emaciation and muscu- 

 lar weakness. This disease terminates fatally in the course of two to 

 four weeks. Contrary to the effect of total extirpation, the removal 



^ Harvey Lectures, New York, x, 1915. 



2 Sebolew, Virchow's Archiv, clxviii, 1902, 91, and Homans, Journ. of Med. 

 Research, 1914. 



3 Archiv ftir exp. Path, und Pharm., xxi, 1893, 85. 



