30 APPENDIX. 



Oftte Uses of the JBile. Various opinions have been entertained by physiologists re- 

 specting the purposes of the bile. " Some have supposed that the secretion of bile is 

 merely excrementitious ; others that the bile is intended to stimulate the intestine, and 

 to produce a ready evacuation of the faeces ; and another opinion has been, that the 

 bile is poured out into the duodenum, that it may be blended with the chyme, and by 

 producing chemical changes in it, convert it into chyle. The situation of the liver, con- 

 nected as it is in every instance with the upper part of the alimentary canal, is unfa- 

 vourable to the first of these hypotheses ; but the last is rendered very probable by the 

 circumstance of chylincation taking place just at the part where the bile flows into the 

 bowel." 



In order to arrive at some satisfactory conclusion on these points, Mr. Brodie applied 

 a ligature round the choledic duct of an animal, so as completely to prevent the bile 

 entering the intestine, and then noted the effects produced on the digestion of the food 

 which the animal had swallowed, either immediately before or immediately after the 

 operation. The experiment was repeated several times, and the results were uniform. 

 Before he describes these results, he remarks, that the " application of a ligature round 

 the choledic duct is easily accomplished, and with very little suffering to the animal ; 

 so that any derangement in the functions of the viscera, which follows, cannot reasona- 

 bly be attributed to the mere operation. The division of the stomachic ropes, or ter- 

 minations of the eighth pair of nerves on the cardia of the stomach, and the ligature of 

 the whole extremity of ihe pancreas, are operations of much greater difficulty : yet it 

 has been ascertained that neither of these at all interfere with the conversion of the 

 food into chyme, or that of the chyme into chyle-" 



" When an animal," Mr. Brodie proceeds to state, swallows solid food, the first 

 change which it undergoes is that of solution in the stomach. In this state of solution 

 it is denominated chyme. The appearance of the chyme varies according to the nature 

 of the food. For example, in the stomach of a cat the lean or muscular part of animal 

 food is converted into a brown fluid, of the consistence of thin cream ; while milk is 

 first separated into its two constituent parts of coagulum and whey, the former of 

 which is afterwards redissolved, and the whole converted into a fluid substance, with 

 vexy minute portions of coagulum floating in it. Under the ordinary circumstances, 

 the chyme, as soon as it has entered the duodenum, assumes the character of chyle. 

 The latter is seen mixed with excrementitious matter in the intestine ; and in its pure 

 state ascending the lacteal vessels. Nothing like chyle is ever found in the stomach j 

 and Dr. Prout, whose attention has been much directed to the chemical examination of 

 these fluids, has ascertained, that albumen, which is the principal component part of 

 chyle, is never to be discovered higher than the pylorus. Now, in my experiments, 

 which were made chiefly on young cats, where a ligature had been- applied so as to ob- 

 struct the choledic duct, the'first of these processes, namely, the production of chyme 

 in the stomach, took place as usual ; but the second, namely, the conversion of the 

 chyme into chyle was invariably and completely interrupted. Not the smallest trace 

 of chyle was perceptible either in the intestines or in the lacteals. The former contained 

 a semi-fluid substance, resembling the chyme found in the stomach with this difference, 

 however, that it became of a thicker consistence in proportion as it was at a greater dis- 

 tance from the stomach ; and that, as it approaches the termination of the ileum in the 

 csecum, the fluid part of it had altogether disappeared, and there remained only a solid 

 substance, differing in appearances from ordinary fxces. The lacteals contained a trans- 

 parent fluid, which I suppose to have consisted partly of lymph, partly of the more fluid 

 part of the chyme, which had become absorbed. 



" I conceive that these experiments are sufficient to prove that the office of the bile 

 is to change the nutritious part of the chyme into chyle, and to separate from it 

 the excrementitious matter. An observation will here occur to the physiologist. If 

 the bile be of so much importance in the animal economy, how is it that persons occa- 

 sionally live for a considerable time, in whom the flow of bile into the duodenum is in- 

 terrupted ? On this point it may be remarked, 1st, That it seldom happens that the 

 obstruction of the choledic duct from disease is so complete as to prevent the pas- 

 sage of the bile altogether; and the circumstances of the evacuations being of a white 

 colour may prove the deficiency, but does not prove the total absence of bile. 2ndly, 

 That in the very few authenticated cases which have occurred, of total obliteration of 

 the choledic duct in the human subject, there has been, I believe, always extreme 

 emaciation, showing that the function of nutrition was not properly performed. 3dly, 

 That the fact of individuals having occasionally lived for a few weeks or months under 

 these circumstances only proves that nutrition may take place to some extent without 

 chyle being formed. In my experiments I found that the more fluid parts of the 

 chyme had been absorbed, and probably this would have been sufficient to maintain 

 life during a limited period of time." (Journal of Science and the *%rts, No- 28.) 



