CHEMICAL BASIS OF THE ANIMAL BODY. 143 



The final filtrate is then concentrated to crystallisation, and the taurin 

 finally purified by recrystallisation from water. The use of the lead 



FIG. 8. TAURIN CRYSTALS. (After Kiihne.) 



salt may be omitted in many cases and the taurin purified by several 

 crystallisations from water. 



The behaviour of taurin when introduced into the alimentary canal is remarkable. 

 In the case of man the larger part reappears in the urine in combination with 

 carbamic acid as tauro-carbamic acid. In dogs a large part is excreted unaltered 

 together with some tauro-carbamic acid. In herbivora (rabbit) on the other hand a 

 portion of it is excreted in the urine, but the larger part is oxydised, leading to a 

 large increase of sulphates in the urine together with some hyposulphites. Injected 

 subcutaneously it is largely excreted in an unaltered form 1 . 



Tauro-carbamic acid. NH 2 CO . NH(CH 2 ) . CH 2 . (S0 2 OH). The remarks which 

 have been already made respecting the nature and formation of sarkosin-carbamic 

 acid apply generally to this acid. It is most easily obtained as a potassium salt 

 by the action of potassium cyanate on taurin 2 . 



4. Kreatin. C 4 H 8 N 3 0, [NH : C<?< CH > 



JN rl 2 

 (Methyl-guanidinacetic acid.) 



By the union of ammonia with cyanamide a strongly alkaline base, 

 guanidin is obtained: CN . NH 2 + NH 3 = NH . C (NH 2 ) 2 (see below). 

 When sarkosin is employed instead of ammonia a similar reaction 

 takes place, resulting in the formation of kreatin : 

 CN.NH 2 + CH 2 .NH (CH 3 ). COOH=NH: C(NH 2 ) . N(CH 3 ) .CH 2 .COOH. 3 

 Since sarkosin is methyl-amidoacetic acid it is at once obvious that 



1 Salkowski, Ber. d. d. chem. Gesell. 1872, S. 637. Virchow's Arch. Bd. LVIII 

 (1873); S. 460. 



2 Salkowski, Virchow's Arch. Bd. LVIII. (1873), S. 460. Ber. d. d. chem. Gesell. 

 1873, Sn. 744, 1191, 1312. Huppert, Ibid. 1278. 



3 Volhard, Sitzb. d. bayer. Akad. 1868, Hft. 3, S. 472. Also Zt. f. Chem. 1869, 

 S. 318. 



