290 CONSTITUENTS OF THE BILE ENUMERATED. [BOOK II. 



Reaction of The bile is a feebly alkaline liquid. According to 

 the bile. Bidder and Schmidt its alkalinity depends on admix- 



ture with the secretion of the gall-bladder. In order to determine 

 its reaction the bile should be previously diluted. 



SECT. 4. ENUMERATION OF THE CONSTITUENTS OF THE BILE. 

 THE CONSTITUENTS WHICH ARE SPECIFIC OF THE SECRETION. 



The bile is an aqueous solution containing as its principal and specific 

 constituents (1) the sodium salts of certain conjugated acids comprised 

 under the general designation of bile acids ; (2) certain colouring 

 matters, included under the general term of bile colouring matters, of 

 which the principal are bilirubin, the characteristic colouring matter 

 of the bile of the carnivora, and biliverdin, which is characteristic of 

 the bile of the herbivora. Amongst the characteristic constituents 

 of the mixed bile should perhaps be also included (3) the mucoid 

 nucleo-albumin which is mixed with the bile in the gall-bladder. 

 We speak of the bile acids and bile colouring matters being specific 

 constituents of the bile and specific products of the liver, inasmuch 

 as these substances are not found in the blood or in the tissues of 

 animals from which the liver has been removed 1 . We cannot with 

 equal positiveness speak of the mucoid nucleo-albumin being a 

 specific constituent, as bodies of somewhat similar composition and 

 reactions occur elsewhere ; besides, this constituent is not a product 

 of the activity of the hepatic cells and must be looked upon, in a 

 sense, as an adventitious constituent of the bile. 



In addition to the bodies which are the specific products of the 

 activity of the hepatic cells and the mucoid nucleo-albumin, the bile 

 contains cholesterin, neutral fats, soaps, lecithin, or its products of 

 decomposition, traces of a diastatic ferment, mineral matters, amongst 

 which a small quantity of iron is invariably found, and gases of 

 which the chief is C0 . 



'2' 



SECT. 5. GLYKOCHOLIC ACID, TAUROCHOLIC ACID, HYOGLYKO- 

 CHOLIC ACID, HYOTAUROCHOLIC ACID, CHENOTAUROCHOLIC 

 ACID. 



Introductory Observations. 



If the bile of the ox be mixed with animal charcoal and evapo- 

 rated to dryness on the water bath, a pulverisable residue is obtained. 

 This when treated with absolute alcohol yields a colourless or faintly 

 yellow solution, containing no trace of the bile colouring matters, but 

 which holds in solution the sodium salts of the bile acids. If now 

 anhydrous ether be added to this alcoholic solution, a white turbidity 



1 In old blood extravasations, microscopic crystals of so-called haematoidin occur 

 which appear to be identical in crystalline form, colour, spectroscopic characters and 

 chemical reactions with bilirubin. 



