103 



PANCREAS. 



pose, an}' ssparation between the pancreatic 

 fluid and the fatty matters. After the lapse 

 of some hours it became evident that the 

 fat had not only been minutely subdivided 

 and emulsified, but that it had, furthermore, 

 been chemically modified. In fact the neu- 

 tral fatty matter and the alkaline pancreatic 

 juice, constituting at the moment of mixture 

 a white liquid with an alkaline reaction, had, 

 five or six hours afterwards, acquired a re- 

 action distinctly acid. In examining what 

 had taken place, it was easy to show, by the 

 ordinary means, that the fatty matter had 

 been decomposed into glycerine and a fatty 

 acid. In the test-tube in which the butter 

 had been subjected to the action of the pan- 

 creatic fluid, the butyric acid was easily 

 recognised, even at a distance, by its charac- 

 teristic odour. Bernard then goes on to prove, 

 by the method of elimination, the unicity and 

 propriety of this property of the pancreatic 

 secretion, by showing that no other fluid in 

 the body bile, saliva, gastric juice, serum, 

 the cephalorachidian fluid is capable of ex- 

 citing it : all these fluids mixed with the 

 various fatty matters failed in producing an 

 analogous effect in any degree. 



This instantaneous emulsion, however, of 

 neutral fatty matters, and their separation 

 into glycerine and a fatty acid, is only effected 

 by normal pancreatic juice ; that is to say, a 

 pancreatic juice, alkaline, viscid, and coagu- 

 lating in a mass by heat or the strong acids. 

 If, on the other hand, the oil is mixed with 

 a morbid or altered specimen of the secretion 

 that is, watery, without viscosity, and not 

 coagulating by heat, its action on the fatty 

 matters is nil, and a speedy separation takes 

 place between the inert pa'ncreatic fluid and 

 the unmodified fatty matter. 



Taking as a postulate the admitted fact, 

 that it is the white, opaque, milky chyle alone 

 that contains fatty matter, Bernard then pro- 

 ceeds to show by experiments on the living 

 animal, that fatty matter thus modified alone 

 finds its way into the lacteals, is alone ab- 

 sorbable, and that it is the pancreatic juice 

 only that is capable of effecting this change. 

 In all dogs killed in mid-digestion of fatty 

 aliments, the fat was merely fluidified by the 

 heat of the stomach, retained all its charac- 

 ters, and, on the application of cold, congealed 

 on the surface of the gastric juice like the 

 fat on broth. In the intestine, on the con- 

 trary, below the openings of the pancreatic 

 duct, the fat could not be distinguished by 

 these characters, but formed a pultaceous, 

 creamy, emulsive material ; and the lacteals 

 were gorged with a white, homogeneous, 

 milky chyle. But when the pancreatic ducts 

 were tied, the fat remained unaltered in the 

 intestine, and the lacteals contained nothing 

 but a limpid chyle free from all fatty material, 

 which had ceased to be absorbed in con- 

 sequence of the abstraction of the pancreatic 

 secretion. 



Furthermore, in the rabbit (in which, by 

 an arrangement altogether exceptional, the 

 pancreatic duct opens into the intestine at a 



distance of 10 or 12 inches from the pylorus), 

 another proof of the same fact may be ob- 

 tained without any ligature or mutilation. 

 If a rabbit be crammed with lard, and the 

 intestines examined in mid- digestion, the fat 

 contained in the small intestine above the 

 opening of the duct will be found unchanged, 

 while that immediately below and downward 

 has undergone the emulsifying process. The 

 lacteals, also, above that point are filled with 

 a limpid chyle, while those arising immediately 

 below are conspicuous for their milky, opaque 

 contents. It is impossible, as Bernard says, 

 to find, in the whole range of experimental 

 physiology, a more elegant and simple method 

 of proof. 



The tardiness of physiologists in the dis- 

 covery of this function may be explained, 

 Bernard thinks, by their minds being pre- 

 occupied with the false notion that the pan- 

 creatic secretion was analogous to the saliva ; 

 and the assignation of this function to the 

 bile by Sir Benjamin Brodie, he accounts for 

 thus. Brodie performed his experiments on 

 cats, and found that, after ligature of the cho- 

 ledoch duct, the lacteals contained no fat, and 

 that the chyle was limpid and transparent. 

 Shortly after, Magendie, with the view of 

 verifying these experiments, repeated them 

 on dogs, but found that the absorption of the 

 fat and the whiteness of the chyle were in no 

 way interfered with by the ligature of the 

 gall-duct. Now in cats the pancreatic duct 

 joins the choledoch before it enters the intes- 

 tine ; so that it is conceivable that Sir Benj. 

 Brodie, having only in view the action of the 

 bile, and attaching no importance to the pan- 

 creatic canal, had tied the one with the other : 

 and thus the absence of fatty matter in the 

 chyle may be explained. But in dogs the 

 choledoch is completely separate from the two 

 pancreatic ducts, so that after its ligature the 

 flow of the pancreatic juice remains perfectly 

 free, the fat continues to be emulsified, and 

 the chyle to possess its characteristic white- 

 ness. These experiments, therefore, are en- 

 tirely in accord, and the difference of their 

 results is strictly assignable to the different 

 disposition of the ducts in the animals on 

 which they were respectively performed. 



Some little time ago, while engaged with 

 Dr. Todd in some investigations upon this 

 subject, I tied the gall-duct in some score of 

 dogs, and invariably found that its ligature in 

 no way interfered with the absorption of the 

 fat and the perfect elaboration of the chyle. 

 As long as the supply of the pancreatic secre- 

 tion was not interfered with, the emulsifying 

 of the fat was complete, and its absorption 

 entire. I also repeated Bernard's experi- 

 ments on rabbits, and obtained results in 

 perfect accord with his views. I injected 

 melted lard into the stomach, then gave them 

 a meal of green food, and killed them in three 

 or four hours. The point of im mergence 

 of the pancreatic duct was most distinctly 

 that of the commencement of the opacity of 

 the chyle : the lacteals above were filled with 

 a fluid clear and limpid. 



