CRYSTALLIZABLE NITROGENOUS MATTERS. 



105 



Fig. 21. 



SODIUM GLYOOOHOI.ATI! FROM OX-BILB, 



after two days' crystallization. At the lower 

 part of the figure the crystals are melting into 

 drops, from evaporation of the ether and absorp- 

 tion of moisture. 



with absolute alcohol, the alcoholic solution decolorized with animal 

 charcoal, and then mixed with from 8 to 10 times its volume of ether. 

 A whitish precipitate is thrown 

 down which soon collects into 

 little drops and masses, of a 

 consistency like that of Canada 

 balsam, whence the biliary salts 

 have been sometimes termed the 

 " resinous" matters of the bile. 

 In the course of 24 hours, 

 sometimes only after four or 

 five days, the sodium glyco- 

 cholate crystallizes abundantly 

 in the form of hemispherical or 

 star-shaped masses of fine ra- 

 diating acicular crystals. These 

 crystals may be preserved in- 

 definitely in the mixture of al- 

 cohol and ether ; but if the mix- 

 ture be poured off, the cold 

 produced by evaporation causes 

 a condensation of atmospheric 

 moisture and a rapid melting 



and solution of the crystals, which may be seen under the microscope 

 liquefying into transparent, rounded,, oleaginous-looking drops. The 

 solubility of these drops in water and their insolubility in ether will 

 readily distinguish them from oil globules, which they closely resemble 

 in their optical properties. Sodium glycocholate may be precipitated 

 from its watery solution by both the neutral and tribasic lead acetates. 

 Its alcoholic solution rotates the plane of polarization toward the right 

 25.T. 



Sodium Taurocholate, C 26 H 44 NS0 7 Na. 



This is a substance similar in many of its properties to the last, and, 

 like it, a peculiar ingredient of the bile. Its organic acid, taurocholic 

 acid (C 26 H 43 NS0 7 ), is distinguished by containing an atom of sul- 

 phur, owing perhaps to its having been derived from the albuminous 

 matters. If so, glycocholic acid will represent a product of further 

 oxidation, under which sulphur, hydrogen, and oxygen are given up in 

 such proportions that the products of elimination are sulphuric acid and 

 water, as follows : 



Taurocholic acid. Glycocholic acid. 



C 26 H 45 NS0 7 - S(H a O) = C 26 H 43 N0 6 . 



By boiling with dilute acids or alkalies, or even in water, taurocholic acid 

 is decomposed with the formation of two other bodies, namely, taurine 

 (C 2 H.NSO. S ), a neutral nitrogenous substance, containing all the sulphur, 

 so called because first discovered in bullock's bile, and cholic acid 



8 



