

THE PANCREAS AND THE LIVER 121 



But you may ask, how do we know that the pan- 

 creas develops an internal secretion the hormone 

 of which travels through the blood to the liver? 

 Why cannot we assume that whatever influence the 

 pancreas exerts on the liver is due to its external 

 secretion to the pancreatic juice which, by means 

 of a duct, is poured into the small intestine? We 

 can answer these questions very definitely. It has 

 been shown that incomplete removal of the pan- 

 creas as little as one-fourth to one-fifth of the to- 

 tal need be left prevents diabetes, even though 

 all connections with the small intestine have been 

 interrupted, and all flow of pancreatic juice has 

 stopped. Or again, the ducts of the gland may be 

 tied, or, what amounts to the same thing, filled with 

 paraffin, and no glycosuria results. But the most 

 convincing proof that the pancreas develops an in- 

 ternal secretion is this : after complete extirpation 

 of the gland, and after the onset of the disease, the 

 symptoms of diabetes disappear upon the grafting 

 of a piece of pancreas under the skin or into the 

 abdominal cavity. Here whatever communication 

 is open between the grafted pancreas and the other 

 organs of the body is by means of the blood and 

 the blood only. 



Kecent experimentation tends to show that the 

 internal secretion of the pancreas is not developed 

 by the pancreatic cells themselves but by peculiarly 

 shaped groups of cells, scattered throughout the 



