CHAP. VIII.] METHODS FOR THE ANALYSIS OF BILE. 



393 



5. Determi- 

 nation of the 



of" 1 the S biie 

 acids, of the 

 quantity of the 



the alkaline 

 metals com- 

 bined with 



weight of the ash from that of the dried precipitate, the weight of 

 the mucoid nucleo-albumin is obtained. 



4. Determi- A quantity of about 10 grammes of bile is treated 

 nation of neu- w ith alcohol exactly as stated under 3, the precipitate 

 trai fats, soaps Q f t k e muco id-nucleo albumin being carefully washed 

 L with ether. The alcoholic and ethereal solutions are 

 evaporated to dryness and the residue thoroughly extracted with 

 alcohol and ether, filtered, evaporated to dryness and weighed. Thus 

 is found the combined weight of the cholesterin, lecithin and neutral 

 fats. In order to obtain the separate amounts of these constituents, 

 proceed exactly as prescribed for the determination of these bodies 

 in the blood (Hoppe-Seyler's method, Vol. I. 1st edition, p. 187). 



The determinations under this head necessitate a 

 thorough training in the methods employed and should, 

 w ^h ^ e exception of the first and simplest, not be 

 attempted by inexperienced chemists. 



( a ) The simplest, but only approximate, method of 

 of determining the amount of the salts of the bile acids in 

 the bile, is to evaporate a weighed quantity of bile to 

 dryness, after mixing it with pure animal charcoal. The 

 thoroughly dried residue is extracted with boiling ether 

 and afterwards repeatedly with boiling alcohol. The 

 alcohol solutions are filtered, evaporated in a weighed porcelain 

 crucible until the weight of dry residue is constant ; thereafter the 

 residue is ignited, the weight of the ash being deducted from that of 

 the total alcoholic residue. Thus we obtain approximately the 

 weight of bile acids. 



(6) (Hoppe-Seyler's method.) 30 grammes of bile are treated 

 exactly as described under 3 (p. 392) ; indeed the same quantity of 

 bile which serves to furnish the amount of the mucoid nucleo- 

 albumin will, if not too scanty, suffice for the determinations now 

 being considered. 



The mixed alcoholic solution is completely precipitated by adding 

 many times its volumes of anhydrous ether. The precipitate which 

 separates consists principally of the alkaline salts of the bile-acids, 

 but contains also small quantities of the alkaline salts of the fatty 

 acids and of oleic acid, besides sodium and potassium chloride. The 

 precipitate is allowed thoroughly to subside and, after decantation of 

 the alcohol and ether, is dissolved in distilled water ; the solution, 

 having been diluted to a known volume or weight, is divided into 

 three parts, of known if not of equal volume or weight ; these we 

 shall designate a, fi, 7. The fraction a is evaporated to dryness, first 

 on the water bath, then at 110 C, and after weighing is ignited, 

 and the ash is then weighed. In the ash the quantity of chlorine, 

 potassium and sodium are determined by the ordinary methods. 



The fraction @ serves for the determination of the amount of 



