510 APPENDIX. 



different results. Brodie,* as well as Tiedemann arid Gmelin,t 

 thought that they had convinced themselves that after tying the 

 common bile-duct, the lacteals contained a colourless, transparent 

 fluid, notwithstanding the use of fat food, whilst Magendie,J and 

 more recently* even Lenz, in connection with Bidder and 

 Schmidt, have seen the chyle appear milk-white under similar 

 relations. If it maybe a priori anticipated that we cannot form a 

 very definite opinion of the more or less white colour, or of the 

 greater or less transparency of the chyle contained in the lacteals, 

 the uncertainty of this mode of observation must be doubly mani- 

 fest to all those who have frequently observed the lacteals in 

 animals which have been killed immediately after feeding. Hence 

 it follows that, as we have already seen, even when the bile is 

 excluded, a portion of the fat is resorbed, and renders the chyle 

 more or less whitish. The quantitative determination was here 

 the only way of deciding the question with certainty, and 

 this was, therefore, the course which Schmidt pursued. In 

 the chyle obtained from the thoracic duct of dogs with biliary 

 fistulse, he found on one occasion 0'834 of fatty acids mixed with 

 other organic substances, and on another occasion 0'190^ of free fat 

 together with 0*1 13 of fatty acids, while the chyle of a healthy 

 dog, that 8 hours before its death had been fed upon beef, con- 

 tained 3'244-g- of free fat, with O'OSSg- of fatty acids. While the 

 differences in the amount of fat in these two kinds of chyle are so 

 great, the other constituents were found to fluctuate very slightly 

 in their quantitative relations. Moreover, this experiment perfectly 

 confirms the fact which had been otherwise established, that the 

 bile essentially contributes to the absorption of fat. 



If it be rendered tolerably evident by these experiments, that 

 the bile is indispensable to the absorption of fat into the juices of 

 the animal organism, its mode of action in this process still remains 

 unexplained : and this result must appear the more striking, seeing 

 that direct experiments instituted with fat and bile afford no clue 

 to the explanation of the mode of action. The bile possesses in a 

 far less degree than the pancreatic juice the power of forming an 

 emulsion, and even if it did possess this property in a well-marked 

 degree, the resorbability would be by no means explained by the 

 extreme comminution of the fat ; for since the coats and cells of the 



* Quarterly Journal of the Sciences and Arts. 1853, Jan. 

 t Die Verdauung nach Versuchen. Bd. 2, S. 24-48. 

 $ Precis e'tementaire de Physiologic. T. 2, p. 117. 

 Op. cit. p. 58. 



