250 INTESTINAL DIGESTION. 



Action of the Pancreatic Juice upon Fats. The pancreatic juice is the 

 only one of the digestive fluids which is capable of forming a complete and 

 permanent emulsion with fats. The fact that the other digestive fluids will 

 not accomplish this is easily demonstrated as regards the saliva, gastric juice 

 arid bile. The intestinal juice is then the only one which might be supposed 

 to have this property. The observations of Busch on this point, in his case 

 of intestinal fistula, are conclusive. He found that fatty matters taken into 

 the stomach were discharged from the upper opening in the intestine in the 

 form of a fine emulsion and were never recognizable as oil ; but that fat 

 introduced into the lower intestinal opening was not acted upon and was 

 discharged unchanged in the faeces. The emulsion resulting from the action 

 of pancreatic juice upon fats persists when diluted with water and will pass 

 through a moistened filter, like milk. This does not take place in the imper- 

 fect emulsion formed by a mixture of oil with any other of the digestive fluids. 

 Although the normal pancreatic juice is constantly alkaline, this is not an 

 indispensable condition as regards its peculiar action upon fats; for the 

 emulsion is none the less complete when the fluid has been previously neu- 

 tralized with gastric juice. These facts with regard to the action of the 

 pancreatic juice upon fats were first ascertained by Bernard, in 1848. 



A substance called steapsine, extracted from the fresh pancreas, has the 

 property of decomposing fats into the fatty acids and glycerine, but the 

 fatty acids do not appear in the chyle. The emulsification of the fats by the 

 pancreatic juice is to a great extent a mechanical process dependent upon 

 the general physical characters of the fluid ; but although the fat which is 

 contained in the lacteal vessels is always neutral, it is thought that steapsine 

 assists in rendering the emulsion fine and permanent. 



The cases of fatty diarrhoea connected with disorganization of the pan- 

 creas, which were reported by Richard Bright, in 1832, apparently did not 

 direct the attention of physiologists to the uses of this organ. These cases, 

 with others of a similar character which have been reported from time to 

 time, are now brought forward as evidence of the action of the pancreas in 

 the digestion of fats. Many of them presented a train of symptoms anal- 

 ogous to those observed in animals after partial destruction of the gland. 

 The presence of fat in the alvine dejections was marked ; and as is now well 

 known, this could be nothing but the undigested fatty constituents of the food. 

 In the three cases observed by Bright, the pancreas was found so disorga- 

 nized that its secreting action must have been almost if not entirely abol- 

 ished. In the case reported by Lloyd, the condition was the same ; and in 

 the case reported by Elliotson, " the pancreatic duct and the larger lateral 

 branches were filled with white calculi." Another case of disease of the 

 pancreas was described in the catalogue of the Anatomical Museum of the 

 Boston Society for Medical Improvement, in 1847. In this case it was ob- 

 served 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 cases of this character have been 



