go PRACTICAL PHYSIOLOGY. [XI. 



(rf.) Favours Filtration and Absorption. — Place two small fiinnels ex- 

 actly the same size in a filter-stand, and under each a beaker. Into each 

 funnel put a filter-paper ; moisten the one witli water (A), and the other with 

 bile (B) ; pour into both an equal volume of almond-oil ; cover with a slip ol 

 glass to prevent evaporation. Set aside for twelve hours, and note that the 

 oil passes through B, but scarcely any through A. 



(c.) Effect on the Proteid Products of Crastric Digestion. — Digest some 

 fibrin in artificial gastric juice, filter, and to the filtrate add drop by drop 

 ox-bile, or a solution of bile-salts. It causes a white precipitate of pe})tones 

 and acid-albumin. The acid of the gastric juice splits up the bile-salts, so 

 that the bile-acids are also thrown down. 



(/. ) Action on Acid- Albumin. — Prepare acid-albumin in solution (Lesson 

 I.), and add a few drops of bile — be careful not to add too much — or bile-salts. 

 This causes curdling of the whole mass. In {e.) and (/. ) it is better to add 

 bile-salts, because ft-ee hydrochloric acid gives a precipitate with bile. 



ADDITIONAL EXEECISEfS. 



9. Preparation of Taurin (;8-amidooethyl-sulphuric acid C2H7NSO3). — 

 Mix ox-bile with an excess of strong hydrochloric acid, filter from the slimy 

 deposit, and evaporate the mixture— just under boiling-point— whereby a 



tough brownish resinous body separ- 



^^^■p^/^ """^^''l^^'E a-tes— choloidinic acid. Pour oil the 

 ^HH|^ _i^^m acid watery fluid, concentrate it still 



«g|^P*^-r-" - - jK7 f^p^2;^gj.^ until the greater part of the 



^H^la,>, , ,1 >T ,,>- 's^ common salt crystallises out. Mix 



^tS^i' ^wxmisi'^M / the cold mother-liquid with stiong 



^SKkKHKO/ alcohol, whereby taurin is j)recipitated 



^^S^jmUB^^ along with some common salt. Wash 



^^^^^^HRj^^ the precipitate with alcohol, dry it, 



-^^^^^T M tfT T^ y ^^^ dissolve it in a small quantity of 



.^^^^R wwlwlW boiling water. On cooling, taurin 



^^^^ will™' separates in four-sided prisms. 



^^1^^ 10. Cholesterin. — Boil powdered 



If pale gall-stones in water, and then 



Fig. 46.— Double-Walled Filter for Filtering extract them with boiling alcohol. 



Hot Solutions. Filter through a double-walled filter 



kept hot with boiling water (fig. 46). 



The filtrate on cooling precipitates impure cholesterin. Recrystallise it from 



boiling alcohol containing potash, wash it with alcohol and water, and 



dry the residue over sulphuric acid (fig. 16). 



Scheme for Gail-Stones (Salkowski). 



Powdered gall-stones are extracted with ether ; filter. 



I 



Solution evaporated Residue (B) treated on the 

 Cholesterin (A). filter with dilute HCl. 

 L. 



Solution (C) Idme saZU, Residue (D) washed with water, 



dried, treated with chloroform ; 

 Bilirubin. \ 



