1904.] The Chemical Regulation of the Secretory Process. 319' 



on a dog with pancreatic fistula in order to determine whether the 

 amounts of ferments secreted were determined by the nature of the 

 food at any given meal. He was satisfied that his results showed 

 that, even without prolonged adherence to one diet, the composition 

 of pancreatic juice was adapted to the nature of the meal taken. His 

 results do not entirely bear out his contentions, as is seen by the 

 following table, in which it will be noticed that although milk contains 

 no starch it evokes the secretion of a large amount of amylopsin, and 

 that meat causes a secretion of more steapsin than does milk, although 

 this latter contains much more fat than the meat diet. 



Table I. — Results of Walther's Experiments. 



Diet. 



Total amount of enzyme secreted. 



Proteolytic. 



Amylolytic. 



Fat-splitting. 





1044 

 2360 

 1720 



2310 

 6343 

 2498 



4125 

 1218 

 4410 



Of course Walther, as well as the other observers mentioned, 

 regard the adaptation as determined by the stimulation of special 

 nerve endings in the mucous membrane by each constituent of the 

 food, a conclusion hardly borne out by the results just quoted. 

 Another disturbing factor in these experiments is the large variation in 

 total quantity of juice secreted with different food stuffs. 



Table II. — Amount of Pancreatic Juice Secreted for different Food- 

 stuffs (Walther). 



Food. 



Hours of secretion. 



Total 

 amount. 



1. 



2. 



3. 



4. 



5. 



6. 



7. 



8. 



9. 



600 c.c. milk 



8-2 



6 



23-0 



6-2 



1-75 











45 c.c. 



250 grammes 



35 '5 



47-0 



20-5 



16 -5 



10 -o 



12 -0 



65 



3 





151 „ 



bread 





















100 grammes 



45-0 



52 -0 



35 -0 



9-75 













142 „ 



meat 























The quantity of juice secreted will depend on the amount of 

 secretin turned into the circulation, and this, in its turn, on the 

 amount of acid entering the duodenum from the stomach. The 



