QO PRACTICAL PHYSIOLOGY. [XT. 



(d.) Favours Filtration and Absorption. Place two small funnels ex- 

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

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

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

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

 oil passes through B, but scarcely any through A. 



(e. ) Effect on the Proteid Products of Gastric 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 peptones 

 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 free hydrochloric acid gives a precipitate with bile. 



ADDITIONAL EXERCISES. 



9. Preparation of Taurin (jS-amidoaethyl-sulphuric acid C 

 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- 

 ~> ates choloidinic acid. Pour oft the 

 L acid watery fluid, concentrate it still 

 further, until the greater part of the 

 common salt crystallises out. Mix 

 the cold mother-liquid with strong 

 alcohol, whereby taurin is precipitated 

 along with some common salt. Wash 

 the precipitate with alcohol, dry it, 

 and dissolve it in a small quantity of 

 boiling water. On cooling, taurin 

 separates in four-sided prisms. 



10. Cholesterin. Boil powdered 

 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 G all-Stones (Salkowski). 

 Powdered gall-stones are extracted with ether ; filter. 



Solution evaporated Residue (B) treated on the 



Cholesterin (A). filter with dilute HC1. 



Solution (C) Lime salts. Residue (D) washed with water, 



dried, treated with chloroform ; 

 Bilirubin. \ 



