DIABETES AFTER EXTIRPATION OF THE PANCREAS 509 



of those authors who ascribe to the insular apparatus a morphological and 

 embryological independence. Of especial importance for the insular theory, 

 were, more recently, experiments that make a functional independence in high 

 degree possible. 



Already Katz and W inkier had made the observation that after ligation of a larger ex- 

 cretory duct the islands hast for a while, while the glandular parenchyma in the part of the 

 pancreas affected goes to pieces. The general attention was first, however, attracted to this 

 subject by the mutually independent observations of v. Ssobolew and Schulze. Schulze 

 ligated in guinea-pigs a large lobe of the pancreas and found that even after eighty days the 

 islands were retained, while in the sclerotic tissue were found only traces of the acini. 

 Furthermore, it should be mentioned that according to Schulze' s investigation the islands 

 undergo no alteration during fasting, while the pancreatic acini show alterations con- 

 ditioned by the reduced function. Schulze came to the conclusion that the islands are en- 

 tirely independent structures. Ssobolew experimented in rabbits, cats, and dogs. The 

 results in rabbits were the clearest. The pancreas in rabbits, which lies flattened-out 

 between the two layers of the mesentery possesses one excretory duct only. When this is 

 ligated the pancreas shrinks markedly, owing to atrophy of the glandular parenchyma. It 

 is true that Ssobolew found, between the thirtieth and the one hundred and twentieth day 

 after the operation, slight sclerotic alterations of the islands in their clump of sclerotic tis- 

 sue, but later the islands partially recovered; and they were retained even four hundred 

 days after the operation. They also survived after analogous operations in dogs and cats. 

 In dogs, Ssobolew found the atrophy of the glandular tissue less marked, as he supposes 

 that it forms new excretory ducts. Tiberti found, after ligation of the excretory duct in 

 rabbits, at first increased formation of zymogen-granules in the acini, that he regarded as 

 hypersecretion, then hyposecretion, and finally complete cessation of granule formation. 

 Later slight regeneration of the excretory duct made its appearance. In later investiga- 

 tions Tiberti found that the great part of the acini disappeared, and that pictures 

 remain behind whose significance as remaining islands is not clear. In two rabbits, 

 Tiberti found slight glycosuria five months after the operation. In dogs, according to 

 Tiberti's investigations, the sclerosis of the pancreas is less distinct than in rabbits, as 

 islands as well as acini are in part retained. 



Visentini ligated the excretory ducts of the pancreas in twenty-four dogs; he examined 

 the pancreas two hundred and twelve days after the operation and found a gradually pro- 

 gressing sclerosis. Even one hundred and twenty days after the operation individual 

 gland-lobules were found; in two experiments after two hundred and sixty and two hundred 

 and twelve days (respectively) the glandular tissue had entirely gone to pieces. In the 

 dog that survived two hundred and twelve days there was found a slight glycosuria. 



Sauerbeck found after ligation of the excretory duct in rabbits gradually progressing 

 sclerosis of the glandular parenchyma, the islands as in the investigations of Ssobolew 

 showed transitory damages to their structure, owing to the sclerosing process. In 

 this stage, Sauerbeck, in agreement with the older experiments of Hedon often observed 

 glycosuria, sometimes considerable; in later stages the islands again showed their normal 

 structure, and then no glycosuria existed. Lombroso found in forty-one pancreases of dogs 

 that the ligation of the pancreatic duct did not lead unconditionally to sclerosis. Islands 

 as well as acini could be in part retained. 



In ligation of the duct in rabbits, Lombroso and Sacerdote found that the islands \vt-rc- 

 indeed retained, but that their number and size were diminished. 



Finally we should mention the investigations of Zuntz and Mayer. After ligation of 

 the excretory duct of the pancreas, these authors found abundant retention of gland- 

 acini in certain cases, showing more or less alterations of their structure. Very excep- 



