1903.] Adaptation of the Pancreas to different Food-stuffs. 37 



TABLE I. Figures representing the number of c.c. which reduced 

 50 c.c. Pavy's solution. 



Experiment II. Dog fed on milk only for 26 days. 

 Anaesthetised with morphia and HC1 mixture ; pancreatic juice 

 collected. 



Pure lactose solution = 5*167 per cent. 



(a.) 20 c.c. pure lactose solution made up to 200 c.c. 



9'4 c.c. = 50 c.c. Pavy's solution 

 (b.) 20 c.c. lactose solution ^ 



5 c.c. pancreatic juice > Incubated at 37 for 24 hours. 



Few drops CHC1 3 J 



Neutralised, boiled several minutes, filtered, made up to 200 c.c. 



8'8 c.c. = 50 c.c. Pavy's solution. 



These experiments indicate that when dogs are fed on milk, the 

 pancreas secretes a ferment lactase which is capable of inverting 

 milk-sugar, although in dogs not fed on milk no such ferment is present 

 in pancreatic juice. It appears, therefore, that the pancreas does adapt 

 itself to different f ood-stuffs by modifying the composition of its secretion, 

 at any rate as regards the enzymes. 



It is believed by Pawlow and others that this adaptation is carried 

 out entirely by a nervous mechanism, and that a given food reflexly 

 excites the pancreas to secrete a juice specially adapted for the digestion 

 of that particular food-stuff. The same view has been adopted by 

 Weinland, as regards the lactase of the pancreas. In the light of 

 Professor Starling's work on "Secretin," however, it seemed much 

 more probable that the adaptation was due to a chemical stimulus. 



Since lactase is normally present in the intestinal mucous membrane 

 of adult dogs and is increased in amount by a milk diet, it seemed 

 possible that lactase entered the blood stream from the intestine and 

 was picked out by the pancreas and secreted. But the blood of a 

 milk-fed dog was found to have no inverting action on lactose, nor did 

 intravenous injections of extract of the mucous membrane of the 

 intestines of biscuit-fed dogs cause any secretion of lactase in the 



