422 INTERNAL SECRETION 



from such operation. The brothers Cavazzani, as well as 

 Thiroloix, endeavoured to explain the results of pancreasectomy 

 by the injury to the nerves of the pancreas and liver; their view 

 was based upon experiments in which extirpation of the solar 

 plexus, or of the nerves in the neighbourhood of the pancreas, was 

 followed by glycosuria. The theory of the nervous origin of 

 pancreatic diabetes has recently been warmly advocated by 

 Pfliiger. He points out that, in his experiments with frogs, 

 glycosuria followed, not extirpation of the pancreas only, but also 

 resection of the duodenum and resection of the mesentery between 

 the intestine and the pancreas ; and that, in spite of the avoidance 

 of any injury to the pancreas or disturbance of the pancreatic 

 circulation, this result was constant. Herlitzka obtained similar 

 results. The experiments in which dogs showed glycosuria after 

 extirpation of the duodenum are not regarded as conclusive by 

 Pfliiger, for the reason that the duration of life in such animals is 

 very short; but he draws attention to the earlier experiments by 

 de Renzi and Reale, in which permanent glycosuria lasting until 

 death was observed in dogs after resection of the duodenum. 



That true diabetes follows duodenal extirpation was not con- 

 firmed, however, by Lauwens, Ehrmann, Rosenberg, and 

 Minkowski, who ascribe the occasional slight glycosuria which 

 they observed to nutritional derangement of the pancreas. 

 Minkowski's experiment with a dog in which, after transplanta- 

 tion of the pancreas, the entire duodenum was excised, the animal 

 remaining free from glycosuria for four weeks, at the end of 

 which time the pancreas was removed, when severe diabetes made 

 its appearance is decisive evidence against the occurrence of 

 duodenal diabetes. 



The sole evidence in favour of the duodenum as a causative 

 factor in diabetes is supplied by two clinical cases of Zak's, in 

 which glycosuria followed cauterization of the duodenum ; as well 

 as by the results of certain experiments carried out by the same 

 author, in which, after cauterization of the duodenum, sugar was 

 found to be present in the urine and adrenalin present in the 

 blood (frog's eye test). 



The results of experimental transplantation of the pancreas, 

 and of the extirpation of the organ when performed in several 

 sittings, have completely destroyed the theory that pancreatic 

 diabetes is the result of nervous lesions. Pfliiger suggested that, 

 in cases where the pancreas is implanted under the skin, a minute 

 nerve branch may remain intact, and that by this means the 

 resected nerve fibres may resume their connection with the nerve 

 centres ; this assumption is, however, almost too chimerical to 

 need refutation. Pfliiger himself has modified his views to this 

 extent, that in his latest publication he concedes a certain degree 

 of internal secretory activity to the pancreas. That this internal 

 secretion may be influenced by the nerves is readily conceivable. 



