Dr. KEMP, ON THE NATURE OF THE BILIARY SECRETION. 47 



Having now decided that the bile of the twelve oxen under e.tamination contained an alkaline 

 base, the physical properties of which had been suspended by combination with a body in an 

 opposite electrical condition, the next point was to determine the quantity of soda contained in a 

 given quantity, and thus estimate the combining weight of the organic body with which the 

 base was combined. On this being ascertained, an analysis was made to determine the quantity 

 of organic elements. For the sake of brevity the analyses will be given together, after the 

 description of the manipulations. A further portion of bile obtained from twelve more oxen was 

 now submitted to examination, and the results, both with respect to combining weight and proportion 

 of organic elements, were as nearly identical with the former portion as our present modes 

 of analysis, and the nature of the research, warrant us to expect. It may here be remarked, 

 that animal bodies in general present great obstacles to minute analysis, from the difficulty with 

 which they are burnt, and from the readiness with which they attract moisture. The body 

 contained in the bile is so hygroscopic, that even in the act of mixing and introducing it into 

 the tube a sufficient quantity of moisture is absorbed to render the estimation of hydrogen always 

 too high. Having now determined analytically that the bile of the ox contained an organic electro- 

 negative body in combination with soda, it seemed desirable to attempt a synthetical proof. Here 

 serious objections presented themselves. The bile is more or less influenced by every chemical 

 reagent yet tried, or, to use the words of Berzelius, "it has so great a tendency to undergo changes 

 in its composition, that the action of different reagents upon it converts it into different compounds, 

 which vary according to the processes employed to extract them ; exactly as oils and fats are 

 converted into sugar and fatty acids by the action of the oxides of lead and zinc." It appeared 

 probable, however, on consideration, that by extreme dilution of reagents, and carefully avoiding 

 a greater excess than necessary, we might succeed, if not in isolating the body for analysis, yet 

 in separating it from the soda with which it was originally combined ; uniting it again with a 

 fresh portion of soda, and thus in forming the bile artificially. If the composition of the body 

 thus formed should by subsequent research furnish us with results identical with those obtained 

 from the bile in a natural state, I conceived that no candid person would reject the evidence either 

 as unsatisfactory or unsound. A portion of the dried extract of the bile freed from mucus and 

 fatty acids was dissolved in alcohol of as great a strength as could easily be obtained, and then 

 treated drop by drop with diluted sulphuric acid. The sulphate of soda thus formed being 

 insoluble in alcohol, could of course be separated by filtration, the organic elements previously 

 combined with the soda remaining in solution. The sulphuric acid was added in the slightest 

 possible excess, in order to ensure the complete separation of the soda, and the clear solution obtained 

 by filtration was now treated with an excess of carbonate of soda deprived of its water of crystal- 

 lization. The excess of sulphuric acid was precipitated in the form of sulphate of soda, while 

 a portion of the carbonate readily combined with the electro-negative body remaining in solution. 

 The solution obtained by filtration was now evaporated to dryness, and submitted to analysis. 

 As no change in the physical characters of the body had been made by this process, I was not 

 surprised to find that the combining weight and ratio of organic elements were found by analysis 

 to be identical with the bile in its natural state. But the question may be asked. Why not (having 

 separated the soda by means of sulphuric acid) have evaporated the solution, and then analyzed 

 the body thus isolated ? My reason for not doing so was, that it was necessary to add sulphuric 

 acid in slight excess, and this in proportion as the solution became concentrated by evaporation 

 would have rendered the result unsatisfactory, as we know that sulphuric acid of moderate 

 strength decomposes the bile, and converts it into the choleic and choloidic acids of Demarci'ay. 

 Thus it would have been as much a matter of probable evidence whether the isolated body 

 was the matter contained in the bile, as whether the body separated as above and reconibined with 

 a base, was the electro-negative substance, the composition of which we wished to determine. 

 It now only remains to give a summary of the general results obtained from the analysis of the 

 ox-bile, before passing on to the consideration of the bile of other animals. 



