DIABETES AFTER EXTIRPATION OF THE PANCREAS 503 



According to the views of these authors the islands of Langerhans are com- 

 pletely independent. On the other hand authors state that the insular tissue 

 may shade off into the glandular tissue and vice versa. Laguesse first de- 

 scribed intermediary forms between the gland cells and the island cells, and 

 assumed that on certain functional demands there was a transition from the 

 one kind of tissue into the other (balancement) . Karakaschejf is of the opin- 

 ion that the islands constitute only a sort of reserve material, and that under 

 certain conditions, for examples, in the giving-out of gland tissue, there enters 

 into play a regeneration of the parenchyma from the islands. On the other 

 hand, Gutmann would see a changing of the parenchyma into insular tissue. 

 Also Swale Vincent and Thompson suppose transitions between the gland 

 cells and the island cells. The recent embryological studies and investiga- 

 tions as to the regeneration processes in the pancreas do not seem to confirm 

 the opinion of these authors. 



The pancreas is of entodermal origin. There are present three rudiments, 

 a dorsal, made up of the epithelium of the primitive duodenum, and two ven- 

 tral proceeding from the groove-shaped rudiment of the ductus choledochus. 

 Laguesse first showed that the islands as well as the glandular parenchyma is 

 of epithelial origin, and also showed that the islands separate out from the 

 primitive cell columns at the same time as the glandular tissue. The newer 

 investigations on human fetuses (Pearce, Weichselbaum and Kyrle, Mironescu) 

 leave room for no doubt that the island tissue already in earliest fetal life 

 develops from the epithelial cell columns just as do the acini. 



The youngest fetus in which the islands of Langerhans were observed was 

 54 mm. long (Pearce). Weichselbaum and Kyrle did not find them present 

 as yet in a fetus 50 mm. long. The islands are first found in the distal part 

 of the pancreas. Also in adults they are more frequent in the tail of the pan- 

 creas (Opie). v. Hansemann assumed that the islands were of mesenchy- 

 mal origin, but Weichselbaum and Kyrle found them also later still in asso- 

 ciation with the excretory duct of the pancreas, and hence regarded them as 

 entodermal. Moreover, also the observations as to the regenerative processes 

 in the pancreas after abundant destruction of glandular tissue show that the 

 islands always develop from the excretory duct (Ssobolew, Kyrle) ; especially 

 beautifully do the investigations of Kyrle show that on implantation of pieces 

 of pancreas into the spleen, in the regenerative processes that soon make their 

 appearance, the island and acinous tissue develop independently out of the 

 epithelium of the excretory duct. 



I. EXPERIMENTAL PART 



A. Diabetes after Extirpation of the Pancreas 



We shall first describe carbohydrate metabolism after extirpation of the pan- 

 creas. The complete extirpation of the pancreas causes in all kinds of ani- 



