186 LABORATORY GUIDE IN PHYSIOLOGY. 



operative procedures not properly in the field of this 



chapter.* 



O) To diluted bile add dilute acetic acid. The 

 copious yellow precipitate is mucin. 



() To diluted bile add absolute alcohol; mucin is 

 precipitated; filter. To one portion of filtrate add 

 HC1. The yellow precipitate is glycocholic acid. 



"To the other portion of the filtrate add lead 

 acetate, which throws down lead glycocholate. 

 Remove this by filtration, and to the filtrate add 

 solution of basic lead acetate, which gives a further 

 precipitation of lead taurocholate." [Chemical 

 Physiology, Long, p. 119.] 



(/) Gmeliri 1 s test for bile pigments. To a few cubic 

 centimeters of strong nitric acid in a test tube care- 

 fully add dilute bile. At the junction of the liquids 

 a play of colors, green, blue, violet, red and yellow, 

 will be noted; the green being next to the bile and 

 the yellow next to the acid. This delicate and most 

 reliable test may be applied to any liquid suspected 

 of containing bile. 



(d) The reaction of bile is found to be distinctly 



alkaline. 

 j. Experiments and Observations. 



a. The action of pancre^iti.: juice upon foods. 



(1) To raw or cooked starch add in one beaker 

 aqueous extract of pancreas (a); in another add 

 artificial pancreatic juice (b); place the mixtures in 

 the incubator; after a short time test for reducing 

 sugar. 



*For description of operationsfor the establishment of gastric fistulas, 

 bilary fistulas and pancreatic fistulas, see Hand-book for Physiological 

 Laboratory, Sanderson, pp. 475-517. 



