100 PHYSIOLOGY CHAP. 



dividing the nerves to the pancreatic region, obtained no diabetes, 

 but at most a slight transitory glycosuria. Moreover, Minkowski, 

 Hedon, Thiroloix, Sandmeyer, U. Lombroso, showed that after the 

 extirpation of a large part of the pancreas (leaving only the 

 processus uncinatus freed from all its relations with the duodenum, 

 save the large vessels) there was no glycosuria in the majority of 

 cases, although the lesions involving the nervous system of the 

 region were practically identical with those consequent on com- 

 plete extirpation, so that it was no longer possible for the external 

 secretion to be poured out into the intestine. 



Pfliiger denied the value of this experiment, affirming that 

 if one nerve filament were left intact it was able to act vicariously 

 for all the rest, so that the presence of the nerve plexus which 

 accompanies the respective vessels would explain the absence of 

 glycosuria. 



Hedon, who had already investigated the neural hypothesis, 

 tried to answer this last objection by dividing the neuro-vascular 

 peduncle of the pancreatic segment left in the body. His results, 

 however, proved little, because glycosuria set in after resection 

 of the peduncle; still he noted that it almost always increases 

 when the pancreatic segment is excised. 



The subsequent results of U. Lombroso in Minkowski's 

 laboratory may be regarded as an experimentum crucis against the 

 neural theory. 



In a dog in which the processus uncinatus was grafted under 

 the skin, and which merely showed traces of sugar in the urine 

 (less than 0'3 per cent), the neuro-vascular peduncle was cut a 

 nionth after the first operation. Slight glycosuria appeared, and 

 vanished after four days, leaving the animal in the initial state. 

 After twelve days, on extirpating the segment of the pancreas so 

 as to separate it completely not only from the duodenum but also 

 from the abdominal cavity, severe diabetes at once set in, and 

 persisted till death. 



De Dominicis refused to admit that these experiments, like 

 those which proved that glycosuria does not appear after ligation 

 of the pancreatic ducts, had any conclusive value against his own 

 theory. He pointed out that after ligation of the ducts or 

 excision of that part of the pancreas which contains the ducts, 

 alimentary absorption was far better than after total extirpation 

 of the pancreas. This, according to De Dominicis, showed that 

 the pancreatic secretion was able in some way to reach the in- 

 testine, either by ducts that remained open or by a new formation 

 of ducts. 



With this is associated another question that has recently come 

 under discussion. Does or does not the pancreas influence food 

 absorption, when it is no longer pouring its secretion directly into 

 the intestine ? 



