180 BASIC BODIES. 



dissolves in 15 '5 parts of water, and in 573 of spirit of wine (of 

 0'835 specific gravity,) but is insoluble in anhydrous alcohol and 

 ether, and has no action on vegetable colours. It dissolves, with- 

 out undergoing change, even at the boiling point, in the mineral 

 acids, but forms no compounds with them. It is not precipitated 

 from its solution either by tannic acid or by the metallic salts. On 

 heating, it fuses, puffs up, and developes much acetate of ammonia, 

 and a thick brown oil ; if it be inflamed in the air, it developes 

 much sulphurous acid ; if it be dissolved in caustic potash, and the 

 solution boiled down till it becomes thick, it developes pure am- 

 monia gas, and leaves a residue consisting solely of sulphite and 

 acetate of potash. The sulphur in taurine cannot be detected in 

 the moist way either by nitric acid or by aqua regia. 



Composition. Taurine was first discovered by Gmelin in the 

 bile, and was soon afterwards analysed with very similar results by 

 Dema^ay, Pelouze, and Dumas ; these chemists, however, entirely 

 overlooked the existence of sulphur in this body, the discovery of 

 which was reserved for Redtenbacher,* from whose analyses it was 

 found to consist of : 



Carbon 4 atoms .... 19'20 



Hydrogen 7 .... 5*60 



Nitrogen 1 .... 11'20 



Sulphur 2 .... 25-60 



Oxygen 6 .... 38'40 



100-00 



As this body has not yet been combined with any other in a 

 definite proportion, its atomic weight cannot be determined with 

 accuracy ; but it must not be reckoned among the bases, and we are 

 still perfectly in the dark regarding its rational composition. Red- 

 tenbacherf attempted to elucidate this point ; finding that by the 

 action of potash taurine was decomposed into ammonia, acetic acid, 

 and sulphurous acid, he was somewhat inclined to believe that taurine 

 is a combination of sulphurous acid with aldehyde and ammonia (since 

 2SO 2 + H 3 N + C 4 H 4 O 2 =C 4 H 7 NS 2 O 6 ), and that it might probably 

 be artificially prepared from these substances, as urea is obtained 

 from cyan ate of ammonia. Indeed, on passing sulphurous acid into 

 an alcoholic solution of aldehyde-ammonia he obtained a white crys- 

 talline body isomeric with taurine ; it is however not identical with 

 taurine, but must be regarded as an acid sulphite of aldehyde-am- 



* Ann. d. Ch. u. Pharm. Bd. 57, S. 170-174. 

 t Ibid. Bd. 65, S. 37-45. 



