PANCKEATIC JUICE AND ITS ACTION UPON FOOD. 177 



of the organ, and set free by the solution of the vesicles, fibres, or capil- 

 lary tubes in which they are contained, or among which they are 

 entangled ; and they are still readily discernible, floating in larger or 

 smaller drops on the surface of the semi-fluid alimentary mass. Very 

 soon, however, after its entrance into the intestine, the oily portion of 

 the food loses its characteristic appearance, and is converted into a 

 white, opaque emulsion, which is gradually absorbed. This emulsion 

 is termed the chyle, and is always found in the small intestine during 

 the digestion of fat, entangled among the valvulse conniventes, and 

 adhering to the surface of the villi. The digestion of fatty substances 

 accordingly consists mainly in their emulsion, by which they are con- 

 verted into chyle and made ready for absorption. This change begins 

 to take place in the duodenum, immediately below the orifice of the 

 pancreatic duct. But as the pancreatic and biliary ducts in most ani- 

 mals open into the intestine in company or in close juxtaposition with 

 each other, it might, from this circumstance alone, be doubtful whether 

 the two secretions have not an equal share in producing the effect. Ber- 

 nard first removed the doubt by examining the products of digestion in 

 the rabbit. In this animal, the biliary duct opens, in the usual manner, 

 just below the pylorus, while the pancreatic duct, as stated above, com- 

 municates separately with the intestine 30 or 40 centimetres farther 

 down ; so that there is here a considerable extent of the small intestine 

 already containing bile, but into which the pancreatic juice has not 

 yet been discharged. Bernard fed these animals with substances con- 

 taining oil, or injected melted butter into the stomach ; and, on killing 

 them afterward, found that there was no chyle in the intestine between 

 the openings of the biliary and pancreatic ducts, but that it was abun- 

 dant immediately below the orifice of the latter. Above this point, also, 

 he found the lacteals empty or transparent, while below it they were 

 full of white, opaque chyle. These experiments, which were confirmed 

 by Prof. Samuel Jackson, 1 fully demonstrate that the emulsifying action 

 of the pancreatic juice upon oily matters is exerted within the body 

 during digestion, and is the direct agent in the production of chyle in 

 the intestine. 



Thirdly, the pancreatic juice at the temperature of the living body 

 gradually dissolves coagulated albuminous matters. This property of 

 the secretion, first recognized by Bernard and Corvisart, has been alter- 

 nately confirmed and denied by various subsequent observers. Among 

 those who found in the pancreatic juice more or less power of this kind, 

 some stated it to be only present when the fluid was acidulated (Meissner), 

 while others maintained that it could only be exerted in presence of an 

 alkaline reaction (Wundt) ; and the information obtained in regard to 

 the process has been generally much less distinct and satisfactory than 

 that relating to the other properties of the secretion. The most definite 



1 American Journal of the Medical Sciences. Philadelphia, October, 1854. 



