CHEMICAL BASIS OF THE ANIMAL BODY. 143 



creted in the urine, but the larger part is oxydised, leading to a large 

 iiH-rrase of sulphates in the urine together with some hyposulphite. 

 Injffti-il suhcutaiifously it is largely excreted in an unaltered form. 1 



' ro-carbamic acid. NH a CO . NH(CH a ) . CH 2 . (SO,OH). The 

 remarks which have been already nuule respecting the nature and for- 

 mation of sarkosin-carbaraic acid apply generally to this acid. It is 

 most easily obtained as a potassium salt by the action of potassium 

 cyanute mi taurin. 2 



5, Kreatin. C<H,N 8 O a . [NH : C(^ HS) ' CH..COOH]. 



(M'-ihyl-mianidinacetic acid.) 



By the union of ammonia with cyanamide a strongly alkaline 

 base guanidin is obtained : CN . NH a -f NH 8 = 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 : 

 N NH a +CH a .NH(CH 8 ).COOH=NH : C(NH.,).N(CH 8 ).CH a .COOH.3 

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

 that kn-atin may be regarded as being methyl-guanidinacetic 

 acid. 4 When cyanamide is treated with boiling baryta water it 

 taki-s u\> a molecule of water and yields urea, CN. (NH 2 ) +H a O 

 '(NH 2 ) a , hence as might be expected, kreatin yields by simi- 

 lar treatment sarkosin and urea. This is to the physiologist the 

 most important chemical property of kreatin, bearing as it does so 

 closely upon one possible source and mode of formation of urea in 

 tin- body. (See sub urea.) 



Kivatin occurs as a constant and characteristic constituent of 

 muscles and their extracts to an amount which is variable, but 

 may be taken as from 0'2 - 0-3 p. c. on the weight of the muscle. 6 

 It is also found in nervous tissue, and is said to occur in traces 

 in several fluids of the body. It must however be carefully borne 

 in mind that kivatin very readily loses a molecule of water and 

 thus becomes kivatinin, and that the latter with equal readiness 

 takes up a molecule of water to form kreatiu. Hence the kreatin 

 nhiaiiu'd during any analysis need not at all necessarily imply its 

 presence as such in the original tissue or tin id unless due allow- 

 ance has been made for the possible effect of the methods em- 

 ployed upon the reciprocal conversions of kreatin and kivatinin. 

 This is the cause of the conflicting statements as to the occurrence 

 of kreatin in urine ; as a matter of fact this excretion always con- 

 tains kreatin in. It is on the whole most probable that any 



1 xilkownki, Der. d. d. chem. GeteU. 1872, S. 637. Virchow's Arch. Bd. LVIII 

 (1873) ; S. 4fiO. 



kowski, Virchow's Arch. Bil. i.vm. (IK73), S. 460. Ber. d. d. chem. Gesell. 

 187.3, Sn. 744, II'.M, 1 :!.'. Huj.|Tt. //./,/. 1278. 



Volhard, Sitsb. d. bayer. Akad. 1868, Hit. 3, S. 472. Also Zt.f. Chem. 1869, 

 S. 318. 



4 Cf Horbaczewski, Wien. mrd. Jahrb. 1885, S. 459. 



Voit, Zt.f. Bid. Bd. iv. (1868), S. 77 



