49 2 METABOLISM, NUTRITION, AND DIET 



disease proceeds to a rapidly fatal issue. Opie and others have shown also 

 that in most cases of diabetes mellitus, there are pathological changes in the 

 islands of Langerhans. 



The symptoms produced by total extirpation of the pancreas do not de- 

 pend upon the loss of the pancreatic juice proper to the organism. This 

 secretion may be diverted from the intestine through a pancreatic fistula 

 without the production of diabetes. Moreover, Hedon and Thiroloix have 

 rendered the acini of the gland functionally inactive, and ultimately de- 

 stroyed them, by the injection of paraffin or other substances into the duct 

 of Wirsung, without the supervention of diabetes. 



These experiments have shown that the ordinary secreting cells degener- 

 ate and the islands of Langerhans increase in size, leading to the conclusion 

 that the islands are the structures that produce a special internal secretion 

 which influences or controls carbohydrate metabolism in the body. When 

 the dextrose cannot be readily burned in the body, the content of this sub- 

 stance in the blood is increased and this excess is eliminated by the kidneys. 

 Products of incomplete oxidation of the sugar are also thrown into the circu- 

 lation and eliminated into the urine. In diabetic cases oxybutyric acid, 

 aceto-acetic acid, acetone, etc., are found in the blood and urine. Neither 

 pancreatic nor muscle extracts have the power of burning sugar. 



Banting and Best, 1922, have announced in the Journal of Laboratory 

 and Clinical Medicine a most brilliant demonstration of the isolation and 

 function of an active internal secretion from the pancreas. They per- 

 formed a two stage operation on dogs, the first operation consisting of 

 ligation of pancreatic ducts to induce degeneration of the pancreatic 

 acini. Ten months later they removed this degenerated pancreas and 

 injected watery extracts of it into the circulation of the animal after 

 the development of the usual pancreatic diabetic glycaemia. The blood 

 sugar rapidly augmented after removal of the pancreas, from .09 to over 

 .30 per cent. There was a corresponding glycosuria, as indicated in 

 figure 3160. On injecting 5 cubic centimeters of a four day old extract 

 of the degenerated pancreas, the blood sugar dropped from .27 to .15 

 per cent, but slowly returned to the higher level. Repeated injections 

 of degenerated pancreatic extract continued to depress the amount of 

 blood sugar. These injections greatly reduced the associated glycosuria, 

 see figure 3160. Dr. Macleod, in whose laboratory these experiments 

 were performed, has announced before a scientific medical assembly the 

 extension of these observations. In his laboratory it has been shown that 

 the active principle is easily destroyed by the digestion enzymes and by 

 heat. The active principles must be injected into the blood stream to 

 produce its physiological effect. Furthermore, if the active principle 

 is injected into the blood stream along with an excess of glucose the liver 



