ACTION OF THE PANCREATIC JUICE IN DIGESTION. 275 



Now that the action of the pancreatic juice upon fats is so well understood, it is a 

 matter of surprise that the cases of fatty diarrhoea connected with disorganization of the 

 pancreas, which were reported by Dr. Richard Bright, in 1832, did not direct the atten- 

 tion of physiologists to the function of this organ. These cases, with others of a similar 

 character which have been reported from time to time, are now brought forward as 

 strong evidence of the action of the pancreas in the digestion of fats. Many of them pre- 

 sented a train of symptoms analogous to those observed in animals after partial destruc- 

 tion of the gland. The presence of fat in the alvine dejections was most marked ; and, 

 as is now well known, this could be nothing but the undigested fatty principles of the 

 food. In the three cases observed by Bright, the pancreas was found so disorganized 

 that its secreting function must have been almost, if not entirely, abolished. In the case 

 reported by Mr. Lloyd, the condition was the same ; and, in the case reported by Dr. 

 Elliotson, " the pancreatic duct and the larger lateral branches were filled with white 

 calculi." Another interesting case of disease of the pancreas is described in the catalogue 

 of the Anatomical Museum of the Boston Society for Medical Improvement, in 1847. In 

 this case, it was observed by the patient that fatty discharges from the bowels did not 

 take place unless fatty articles of food had been taken. After death, a large tumor was 

 found in the situation of the pancreas, but all trace of the normal structure of the organ 

 had been destroyed. Many more cases of this character are quoted by Bernard and 

 others, and they fully confirm the observations and experiments which have been made 

 upon the lower animals. They all seem to show that the function of the pancreas in 

 digestion is essential to life, but that one of the chief disorders in digestion incident to the 

 destruction of this gland relates to the digestion of fa^s. 



Taking into consideration all the facts bearing upon this subject, the conclusion is in- 

 evitable that the chief agent in the digestion of fats is the pancreatic juice; and that this 

 fluid acts by forming with the fat a very fine emulsion, thus reducing it to a form in 

 which it can be absorbed. How far the bile may assist in this process is a question which 

 will come up for consideration hereafter; but the facts with regard to the pancreatic 

 juice are conclusive. 



Action upon Starchy and Saccharine Principles. The action of the pancreatic juice 

 in transforming starch into sugar was first observed, in 1844, by Valentin, who experi- 

 mented with an artificial fluid made by infusing pieces of the pancreas in water. Bou- 

 chardat and Sandras first noted this property in the normal pancreatic secretion. Pan- 

 creatine is undoubtedly the principle concerned in the action of this fluid upon starch. 



The property of converting starch into sugar is possessed by several of the digestive 

 fluids. We have seen that the starchy elements of food are acted upon by the saliva, 

 that this action is not necessarily arrested as these principles, mixed with the saliva, 

 pass into the stomach, and that the intestinal juice of itself is capable of effecting the 

 transformation of starch into sugar to a considerable extent. It therefore becomes an 

 important question to determine precisely how far the pancreas is actually concerned in 

 the digestion of this class of principles. 



Bernard places the pancreatic juice at the head of the list of the digestive fluids which 

 act upon starch. This view is undoubtedly correct ; although he goes a little too far 

 in claiming that starch is almost exclusively digested by the pancreas. Bernard's ex- 

 periments, however, were made chiefly on dogs, and these animals do not naturally take 

 starch as food. In man, some of the starchy principles of the food are acted upon by 

 the saliva, but, undoubtedly, most of the starch taken as food is digested in the small in- 

 testine. Although the intestinal juice is capable of effecting the transformation of starch 

 into sugar, the experimental evidence is conclusive that in this it is subordinate to the 

 pancreatic juice, which latter effects this transformation, at the temperature of the body, 

 with extraordinary activity. There is no positive evidence that the bile has any thing to 

 do with this action. 



