3G6 



SECRETION OF PANCREATIC JUICE. [Book ii. 



tion may contribute to the first rise also, but it is more probable 

 that so marked aud sudden a rise as this is carried out by some 



Fig. 83. Diagram illustrating the influence of Food on the Secretion 

 of Pancreatic Juice. (N. O. Bernstein.) 



The abscissa? represent hours after taking food ; the ordinates represent in c.c. 

 the amount of secretion in 10 min. A marked rise is seen at B immediately after 

 food was taken, with a secondary rise between the 4th and 5th hours afterwards. 

 Where the line is dotted the observation was interrupted. On food being again 

 given at 0, another rise is seen, followed iu turn by a depression and a secondary rise 

 at the 5th hour. A very similar curve would represent the secretion of bile. 



nervous mechanism. The details of this mechanism have how- 

 ever not as yet been satisfactorily worked out. 



Stimulation of the medulla oblongata, or of the spinal cord, 

 will call forth secretion in a quiescent pancreas, or increase a 

 secretion already going on. On the other hand a secretion alreadv 

 going on may be arrested by stimulation of the central end of the 

 vagus, and the stoppage of the secretion which has been observed 

 as occurring during and after vomiting is probably brought about 

 in this way. This effect however is not confined to the vagus, 

 it occurs also after stimulation of other afferent nerves, such 

 as the sciatic. 



§ 214. The Secretion of Bile. The act of secretion of bile by 

 the liver must not be confounded with the discharge of bile from 

 the bile-duct into the duodenum. When the acid contents of the 

 stomach are poured over the orifice of the biliary duct, a gush of 

 bile takes place. Indeed, stimulation of this region of the duo- 

 denum with a dilute acid at once calls forth a flow, though 

 alkaline fluids so applied have little or no effect. When no such 



