CHAP. III.] EMULSIONIZIXG PROPERTY OF PANCREATIC JUICE. 211 



It was in the year 184fi that Claude Bernard, being engaged in 

 a comparative study of the process of digestion in carnivorous and 

 herbivorous animals, was struck by the fact that when dogs were fed 

 upon fatty matter this appeared to undergo a modification almost as 

 soon as it passed into the small intestine, whilst when rabbits were 

 similarly fed the change occurred somewhat further from the pylorus. 

 Again, Bernard observed that after a fatty diet the lacteals of dogs 

 were filled with white opalescent chyle from the pylorus downwards, 

 whilst in rabbits the lacteals near the pyiorus did not contain white 

 chyle, while those situated lower down did. Bernard then discovered 

 that this difference in the appearance and absorption of fatty matters 

 coincided with the difference in the situation at which the pancreatic 

 ducts join the small intestine in the dog and rabbit respectively. In 

 the dog the principal duct empties itself, together with the bile duct, 

 into the duodenum very near to the pylorus; whilst in the rabbit the 

 principal duct joins the small intestine from 30 to 35 centimetres (12 

 to 14 inches) below the point of entrance of the bile duct. 



When this relationship had been found to exist between the 

 ation at which the pancreatic juice is poured into the intestine 

 id the situation where fat begins to be modified, it was natural to 

 uire whether the juice was not the active agent in effecting the 

 "ification of fatty matter, and in causing the appearance of 

 ky chyle in the lacteals, and as a result of his investigations 

 aude Bernard was led to the discovery of the facts about to be 

 commented upon 1 . 



The pan- 

 creatic juice Oil or fatty matters which are fluid at the tempera- 

 possesses the ture of the animal body are very readily emulsionized 

 powerofenmi- b th paiicre atic juice, 

 sionizing fats. J J 



If two grammes of alkaline and viscous pancreatic juice be shaken 

 up in a test-tube with one gramme of olive oil, almost instantly, a perfect 

 emulsion is obtained, the liquid resembling milk or chyle ; the same 

 result is obtained if for olive oil we substitute fats, such as butter or 

 mutton suet, which melt at a temperature below 40 C. Temperature 

 appears, to have considerable influence in the process. Thus, when 

 one gramme of lard is agitated with two grammes of fresh, normal 

 pancreatic juice, the process of emulsionizing commences even in the 

 cold, but when the temperature is raised to 35 or 38, a white creamy 

 emulsion is obtained instantly 2 . 



Emulsions obtained in this way are remarkably persistent, and, 

 according to Kiihne 3 , the fat in them exists in even a finer state of 

 division than in milk. 



1 This short account of the way in which Claude Bernard was led to investigate the 

 action of the pancreas is taken from his Lecons de Physiologic Experimentale, Vol. 11. 

 Pp. 178 and 179. 



2 Bernard, Lemons (1856), Vol. n. p. 256. 



3 Kuhne, Lehrbuch, p. 122. 



142 



