3 TO DIGESTION. 



diminish, and from the twelfth hour to the time of feeding, 

 it is at its minimum. 1 The experiments of Dr. Dalton, made 

 on a dog with a fistula into the duodenum, show "that the 

 bile passes into the intestine in by far the largest quantity 

 immediately after feeding, and within the first hour." 2 



Though it has been pretty satisfactorily demonstrated 

 that the presence of the bile in the small intestine is necessary 

 to proper digestion, and even essential to life, and though 

 the variations in the flow of bile with digestion are now well 

 established, it must be confessed that we have hardly any 

 definite information concerning the mode of action of the 

 bile in intestinal digestion and absorption. In all proba- 

 bility, its action is auxiliary to that of the other digestive 

 fluids. 



Movements of the Small Intestine. 



By the contractions of the muscular coats of the small in- 

 testine, the alimentary mass is made to pass along the canal, 

 sometimes in one direction, and sometimes in another ; the 

 general tendency, however, being toward the caecum. The 

 partially digested matters which pass out at the pylorus are 

 prevented from returning to the stomach, by the peculiar 

 arrangement of the fibres which constitute the pyloric mus- 

 cle. The passage from the stomach to the intestine, as we 

 have seen, becomes constricted gradually, so that food of the 

 proper consistence finds its way easily into the duodenum ; 



1 There is some difference in the observations of different experimenters con- 

 cerning the variations in the flow of bile with digestion. Bidder and Schmidt 

 (op. cit.} found that the flow began to increase about two hours after feeding, its 

 maximum being at from twelve to fifteen hours after ; Arnold (American Jour- 

 nal of the Medical Sciences, April, 1856, p. 467) found the maximum to occur 

 soon after feeding, decreasing after the fourth hour ; and Kolliker and Miiller 

 (American Journal of the Medical Sciences, April, 1857, p. 476) found the maxi- 

 mum to be between the sixth and the eighth hour. 



2 DALTON, Constitution and Physiology of the Bile. American Journal of 

 the Medical Sciences, October, 1857, p. 317, and Treati&i on Human Physiology^ 

 Philadelphia, 1864, p. 190. 



