636 INTERNAL SECRETION ENDOCRINE GLANDS 



It is known that in the case of the liver the internal secretion is 

 more important than the external, for an animal cannot survive 

 without its liver, while it may be but little affected by the con- 

 tinuous escape of the bile through a fistulous opening. 



Pancreas. The internal secretion of the pancreas is also indis- 

 pensable. For when the pancreas is excised death follows in many 

 species of animals, and especially in carnivorous animals; and in 

 man severe and ultimately fatal diabetes is often associated with 

 pancreatic disease, while the mere loss of the pancreatic juice 

 through a fistula does not necessarilv shorten life, although the 

 absorption of fat is seriously interfered with. 



The ultimate cause of death seems to be a profound disturbance 

 of metabolism, of which the most significant token is the increased 

 proportion of sugar in the blood, and its speedy appearance in the 

 urine in dogs always within twenty-four hours following total 

 removal of the organ. Associated with the glycosuria is an increase 

 in the quantity of the urine (polyuria), excessive thirst (polydipsia), 

 and a ravenous appetite (polyphagia accompanied by intense 

 hunger contractions of the stomach Luckhardt), in spite of which 

 the animal becomes more and more emaciated in short, the 

 classical symptoms of a severe type of pathological diabetes in man, 

 but, of course, far more acute in their onset, and far more rapid 

 in their progress towards the inevitable end. Dogs rarely survive 

 more than two or three weeks, the immediate cause of the rapidly 

 fatal result being perhaps the extensive suppuration which is apt 

 to ensue on slight and practically unavoidable superficial injuries. 

 The resistance of the tissues to bacterial invasion and their tendency 

 to spontaneous healing are reduced by the overloading of the blood 

 and tissue liquids with sugar. Even when carbo-hydrates are ex- 

 cluded from the food, or when no food at all is given, sugar continues 

 to be excreted in large amounts. The destruction of proteins is 

 increased. It is a significant fact that glycosuria does not appear 

 or is only transient when the pancreas is partially removed, so long 

 as a comparatively small fraction of the gland (one-quarter or one- 

 fifth) is left. Even when such a remnant is dislocated from its 

 original position, care being taken not to interfere with its circula- 

 tion; and sutured in the peritoneal cavity or, indeed, under the skin, 

 the animal remains in good health. In the dog this operation can 

 be practised on the lowest part of the descending division of the 

 pancreas, which is not united with the duodenum, but lies free in 

 the mesentery. Removal of the fragment of pancreas is followed 

 by the whole train of symptoms associated with total extirpation 

 of the organ. 



When the portion of pancreas left is smaller than is sufficient to 

 completely prevent diabetes, only one-eighth of the total mass of 

 the gland, for instance, the symptoms come on more gradually than 



