BY DR. LAUDER BRUNTON. 





lead acetate. This combines with the glycocholic acid, and 

 forms an insoluble lead-glycocholate. Filter, and add to the 

 filtrate lead acetate and ammonia, and a precipitate of lead- 

 taurocholate will be formed. Filter; the filtrate contains the 

 soda which has been set free, and also the excess of lead. 

 The nature of the base may be shown by precipitating the 

 lead from the solution by hydrogen-sulphide, and filtering ; 

 the filtrate when evaporated to dryness leaves sodium acetate. 



*142. Glycocholic Acid (O^H^NOJ is abundant in 

 ox-gall, but is only present in small quantities in human bile, 

 and absent from the bile of the dog and cat. Preparation. 

 Dissolve the lead-glj r cocholate obtained in last experiment in 

 hot alcohol ; precipitate the lead with hydrogen-sulphide, con- 

 centrate the alcoholic solution by evaporation, and then pre- 

 cipitate the glycocholic acid by adding water. 



Another and easier plan is that of Gortop-Besanez. Evapo- 

 rate ox-gall nearly to dryness in a water-bath, and exhaust 

 the residue with alcohol of ninety per cent. (sp. gr. 822). 

 Distil or evaporate off the alcohol, dilute the residue if neces- 

 sary with water, add milk of lime to it and warm it gently. 

 The greater part of the coloring matter will be precipitated by 

 the lime. Filter, allow it to cool, and add dilute sulphuric 

 acid to it (avoiding excess), until a permanent turbidity is 

 produced. Let it stand for a few hours, and the fluid will in 

 most cases become a mass of crystals of glycocholic acid. 

 Occasionally this conversion does not take place till after 

 some days, or even weeks. Throw the mass on a filter con- 

 nected with the water air-pump, wash with cold water, and 

 press it between folds of blotting paper, first with the hand 

 and then with a screw-press. It may be obtained in a still 

 purer condition by dissolving it in a large quantity of lime- 

 water, and adding dilute sulphuric acid" until the glycocholic 

 acid again separates. It crystallizes in long thin white needles. 

 The crystals are sparingly soluble in cold water, more readily 

 in warm, from which it crystallizes out on cooling. It is very 

 sparingly soluble in ether, readily in alcohol. When water is 

 added to the alcoholic solution, the acid is precipitated first 

 as a turbidity, and then in flakes and drops, which become 

 gradually converted into crystals. 



* 143! Glycocine or Glycocol. Glycocholic acid can 

 be decomposed, and glj'cocine obtained from it by boiling it 

 for a long time with strong hydrochloric acid. 1 On then 



1 Glycocine is more readily prepared from hippuric acid, which is 

 contained in large quantities in the urine of herbivora, and consists of 

 glycocine in combination with benzoic acid. Preparation of Hippuric 

 Acid. Milk of lime is added to horse's or cow's urine ; the mixture is 

 boiled, filtered, neutralized with hydrochloric acid, and evaporated to 

 a small bulk. On acidulating with hydrochloric acid, hippuric acid 



