THE INTERNAL SECRETION OF THE PANCREAS 437 



pancreas, namely, the acini and the islands of Langerhans, are 

 concerned in the internal secretory function of that gland. 



According to this author, the internal secretion of the pan- 

 creas not only influences the sugar economy, but also plays a 

 part in the absorption of nutrient material. Previous to Lom- 

 broso, de Domenicis, as has been shown, believed the or/gin of 

 pancreatic diabetes to lie in the disturbance of absorption which 

 he observed after pancreasectomy. Abelmann's experiments 

 (1890) showed that the decomposition of fat is, in a quantitative 

 sense, only slightly affected by total extirpation of the pancreas, 

 but that the absorption of fat entirely ceases after this operation. 

 Fat absorption persists in a greater or less degree after ligf'ure 

 of the excretory ducts, as well as after partial extirpation and 

 transplantation of a portion of pancreatic tissue to a position 

 where it is in communication with the intestine. The absorption 

 of fat in the latter instance has been explained by the assumption 

 that the external secretion of the pancreas becomes re-absorbed 

 and reaches the blood-stream, whence it is conveyed to the in- 

 testinal mucosa. 



Lombroso found that the capacity for the absorption of fat 

 was diminished by extirpation of the pancreas. The fasces of 

 animals without pancreas contain precisely the same amount of 

 fat as their food. If oleic acid is given, a portion becomes 

 absorbed and this is replaced by fat having a higher melting point. 

 After ligature of the excretory ducts, or where the pancreas has 

 ceased to discharge secretion into the intestine, the absorption 

 of fat amounts to about 80 per cent, of the amount of fat given. 

 This absorption is not due to the agency of an external secretion, 

 conveyed by some means into the intestine, but must be ascribed 

 to an internal pancreatic secretion, the activity of which is neces- 

 sary to the metabolism both of the fat in the tissues and that 

 introduced from the exterior. 



It has been advanced against this conclusion that, in Lom- 

 broso's experiments, the measures taken to prevent the external 

 pancreatic secretion from reaching the intestine were insufficient. 

 Hess and Sinn suggest supernumerary excretory ducts ; Visenti 

 points to the possibilities of the ligatured ducts again becoming 

 passable, and of the formation of new ducts. Burckhardt, in one 

 instance, obtained contradictory results and he believes that, in 

 the case of animals with pancreatic fistula, the pancreatic secre- 

 tion may be returned to the intestine by the animals licking 

 themselves. 



Lombroso's results have, however, been confirmed by Zunz 

 and Mayer, and more recently, by R. Fleckseder in a series of 

 extremely careful experiments carried out by methods designed 

 to obviate all sources of error. Fleckseder's conclusion is that 

 the absorptive power of the intestinal mucosa is chiefly dependent 

 upon the internal pancreatic secretion. There is, however, com- 



