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264 SECRETION OF BILE. [BOOK n. 



out a portion of the fundus, sewed together the cut edges of the 

 main stomach, so as to form a smaller but otherwise complete 

 organ, while by sutures he converted the excised piece of fundus, 

 into a small independent stomach opening on to the exterior by a 

 fistulous orifice. When food was introduced into the main stomach 

 secretion also took place in the isolated fundus. This at first sight 

 might seem the result of a nervous reflex act; but it was observed 

 that the secondary secretion in the fundus, was dependent on actual 

 digestion taking place in the main stomach. If the material intro- 

 duced into the main stomach were indigestible or digested with 

 difficulty, so that little or no products of digestion were formed 

 and absorbed into the blood, such ex gr. as pieces of ligamentum 

 nuchae, very little secretion took place in the isolated fundus. We 

 quote this now as bearing on the question of a possible nervous 

 mechanism of gastric secretion, but we shall have to return to it 

 under another aspect. 



Bile. 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 duodenum with a dilute acid at 

 once calls forth a flow, whereas alkaline fluids so applied have 

 little or no effect. This, probably, is a reflex action leading to the 

 contraction of the muscular walls of the gall-bladder and ducts, 

 accompanied by a relaxation of the sphincter of the orifice; 

 it refers therefore to the discharge rather than to the secretion 

 of bile. 



When the secretion of the bile is studied by means of a biliary 

 fistula (which, however, probably induces errors by the total with- 

 drawal from the body of the bile which should naturally flow into 

 the intestine), it is seen to rise rapidly after meals, reaching its 

 maximum in from four to ten hours. There seems to be an im- 

 mediate, sudden rise when food is taken, then a fall, followed 

 subsequently by a more gradual rise up to the maximum, and ending 

 in a final fall to the lowest point ; but it must be remembered that 

 the lowest point is not zero, since the secretion of the bile, unlike 

 that of the saliva and gastric juice, is continuous and even in 

 a fasting animal does not cease. It may be that these variations 

 are due to the action of the nervous system, but experiments have 

 hitherto failed to demonstrate clearly the existence of any distinct 

 nervous mechanism. 



The pressure under which the bile is secreted is in general very 

 low. When a water manometer is connected with the gall-bladder 

 of a guinea-pig, the ductus choledochus being ligatured, the fluid 

 may rise in the manometer to about 200 mm. (equivalent to about 

 16 mm. mercury), but not much beyond. This is of course much 

 less than the arterial pressure in the same animal; but it must not 

 be forgotten that the liver receives its chief blood-supply from a 

 venous source, viz. from the portal vein; and it would appear from 



