BILIN. 47 



soluble in water, y\z. taurin and hydrochlorate of ammonia. 

 — The evaporation of an aqueous solution of the above mix- 

 ture leaves as a residue a crj^stalline mass of taurin and hydro- 

 chlorate of ammonia; the latter may be removed by alcohol of 

 •838, and the taurin may then be recrystallized from a solution 

 in hot water. 



Taurin forms colourless regular six-sided prisms, terminated 

 by foiu'- or six-sided pjrramids. It is hard, craunches between 

 the teeth, has a cooling taste, but is neither bitter nor salt, dis- 

 solves in about sixteen times its weight of water at 60", and is 

 more soluble at a higher temperatm'e. It is very slightly solu- 

 ble in alcohol. It is dissolved without decomposition in con- 

 centrated sulphuric and nitric acids, and gives no reaction with 

 the ordinary reagents. Its composition is represented by the 

 formula C^ N H. Oj^. Hence, as Lowig remarks, it may be 

 regarded as a combination of binoxalate of ammonia and water, 

 for C^ N H, 0,„ = 2 C^ O3 + N H3 + 4 HO. 



On treating the resinous mass, which is insoluble in water, 

 with alcohol, dyslysin is left, and the two acids are dissolved. 

 Dyslysm dissolves with some difficulty in boiling alcohol, and 

 falls again on cooling as an earthy powder. It has not been 

 further investigated. 



Cholinic and fellinic acids are associated in the alcoholic 

 solution. In many respects they closely resemble each other : 

 they are almost insoluble in water, they dissolve in all propor- 

 tions in alcohol, and they form nearly similar compounds with 

 the alkalies, earths, and metallic oxides. Their salts of am- 

 monia and baryta, however, differ in several respects, and by 

 means of these reagents we can isolate the acids. If we evapo- 

 rate a solution of their ammoniacal salts, cholinate of ammonia 

 separates as a white soapy mass, while fellinate of ammonia 

 remains in solution, and appears after due evaporation as a soft, 

 greasy, yellowish substance. 



When an aqueous solution of cholinate of ammonia is decom- 

 posed by hydrochloric acid, cholinic acid separates in light 

 white flocculi, which after drying form a brown pulverizable 

 mass. It is only slightly soluble in ether. The cholinate of 

 baryta is almost insoluble in alcohol. 



Fellinic acid may be exhibited in a similar manner. It sepa- 

 rates from its solution in snow-white flocks, and after drying 



