TAUI1IXE. 149 



MAXN that this acid is a regular cleavage product of keratin substances, and 

 that it can also be obtained from the proteins. FRANKEL l obtained the acid 

 from haemoglobin. The pyroracemic acid obtained by MORNER as a decomposi- 

 tion product from several protein substances originates, according to MORNER, 

 only in part from the cystine. 



Taurine (aminoethylsulphonic acid), C 2 H 7 NSO 3 = ' , has 



not been obtained as a cleavage product of protein substances ; still its 

 origin from proteins has been shown by FRIEDMANN by the close rela- 

 tion that taurine bears to cysteine; and this is the reason why it is 

 treated here in connection with the amino-acids. 



Taurine is especially known as a cleavage product of taurocholic 

 acid, and may occur to a slight extent in the intestinal contents. Taurine 

 has also been found in the lungs and kidneys of oxen and in the blood 

 and muscles of cold-blooded animals. 



Taurine crystallizes in colorless, often in large, shining, 4- or 6-sided 

 prisms. It dissolves in 1516 parts of water at ordinary temperatures, 

 but rather more easily in warm water. It is insoluble in absolute alcohol 

 and ether; in cold alcohol it dissolves slightly, but better when 

 warm. Taurine yields acetic and sulphurous acids, but no alkali sul- 

 phides, on boiling with strong caustic alkali. The content of sulphur 

 can be determined as sulphuric acid after fusing with saltpeter and soda. 

 Taurine combines with metallic oxides. The combination with mercuric 

 oxide is white, insoluble, and is formed when a solution of taurine is boiled 

 with freshly precipitated mercuric oxide (J. LANG 2 ). This compound 

 may be used in detecting the presence of taurine. Taurine is not pre- 

 cipitated by metallic salts. 



The preparation of taurine from ox-bile is very simple. The bile 

 is boiled a few hours with hydrochloric acid. The filtrate from the dyslysin 

 and choloidic acid is concentrated well on the water-bath, and filtered 

 hot so as to remove the common salt and other substances which have 

 separated. The solution is evaporated to dryness and the residue dis- 

 solved in 5-per cent hydrochloric acid, and precipitated with 10 vols. 

 95-per cent alcohol. The crystals are readily purified by r eery st alii za- 

 tion from water. 



The alcoholic solution can be used for the preparation of glycocoll. After 

 the evaporation of the alcohol, the residue is dissolved in water, treated with a 

 solution of lead hydroxide, filtered, the lead removed by H 2 S, and the filtrate 

 strongly concentrated. The crystals which separate are dissolved and decolor- 

 ized by animal charcoal and the solution then evaporated to crystallization. 



1 Morner, Zeitschr. f. physiol. Chem., 42; Suter, Zeitschr. f. physiol. Chem., 20; 

 Friedmann, Hofmeister's Beitrage, 3; with Baer, ibid., 8; Frankel, Sitzungsber. d. 

 Wien. Akad., 112, II, 6, 1903. 



2 See Maly's Jahresber., (>. 



