r/IE EXTRACTIVES OF MUSCLE. 
this means Johnson showed thai creatinine (.1 differenl creatinine Prom 
urinary creatinine) is more abundant in muscle thau creatine, which 
is usually almosl entirely absent. This unexpected result has been 
confirmed by Kemmerich. 1 Creatinine is readily changed into creatine 
by the action of putrefactive micro-organisms. 
Xanthocreatinim (C 5 H 10 N 4 O), crusocreatinine (C 5 H 8 N 4 0), amphierea- 
////'■(( .,1 1 i,,X-< ),), ami pseudoxanthine (C 4 H 5 N 5 0) are leucomaines stated 
by Gautier 2 to be presenl in small quantities. 
Xanthine, hypoxanthine, and uric acid are found in small quantities 
only: the numbers given are as follows : — xanthine, 0'0026 per cent.; 3 
hypoxanthine, 0*022-0"026; 4 uric acid, traces. 5 Uric acid is inure 
abundant in the muscles of reptiles (alligators). The crystalline forms 
of some of the compounds of xanthine 
and hypoxanthine are given in Fig. 17. 
C amine is a crystalline base 
(i ; ir,X 4 0,+HX)), originally found by 
Weidel 6 in large quantities (1 per 
cent.) in American meat extracts, but 
since found in the flesh of many 
animals." It is probably closely re- 
lated to the members of the uric acid 
group just mentioned. 
I " a. — It is generally stated that 
muscle contains little or no urea. 
This statement is chiefly due to the 
fact that it was until recently a 
matter of difficulty to separate 
urea, when only present in small 
quantities, from other nitrogenous hases. In some animals, however, 
the muscular tissue contains a fairly large amount of urea. This is 
the case with the muscles of arthropods. 8 Stadeler and Frerichs 9 
were the first to discover that the organs, including the muscles, 
of Selachian fishes are rich in urea. This was confirmed in the case 
of Selachian embryos by Krukenberg, 10 and more recently hi the 
adult animals by Schroder. 11 In two varieties of dog-fish, the 
mean percentage of urea in the blood was 2 - 61, in muscle T95, and 
in liver T36. Schreeder explains this by the fact that the kidneys are 
sluggish in these animals. By a new method, Schondorff 12 has been 
able to satisfactorily establish the existence of a small quantity of 
urea in the muscles of mammals ; Kaurmann 13 gives the percentage 
Fig. 15. 
-Creatine-zinc chloride crystals. 
— After Kiihne. 
1 Kemmerich, Ztschr.f. physiol. Chein., Strassburg, 1894, Bd. xviii. S. 409. 
- Jahresb. it. <>'. Fortsckr. d. Thier-Chem., Wiesbaden, Bd. xxii. S. 335. 
3 Scherer, Ann. d. Chem., Leipzig, Bd. cvii. S. 314. 
* Neubauer, Ztschr.f. anal. 'hem.. Wiesbaden, Bd. vi. S. 33. 
" Meissner, Ztschr.f. rat. Med., Leipzig, Bd. xxxi. p. 144. 
6 Ann. d. Chem.. Leipzig, Bd. clviii. S. 353. 
7 Krukenberg and Wagner. Sitzungsb. d. phys.-med. Gesellsch. zu Wurzburg, 1883, No. 4. 
See also Jahresb. a. d. Fortsdvr. >< '. Thier-Chem., Wiesbaden, Bd. xi. S. 340. 
8 Krukenberg, Untersuch. a. d. physiol. Inst. d. Univ. Heidelberg, 1881, Bd. iv. S. 33; 
"Vergleich. physiol. Vortrage," 1886,8. 313. 
: ' Journ. f. prakt. Chem., Leipzig, 1858, Bd. lxxiii. S. 48 ; ibid., Bd. lxxvi. S. 58. 
10 "Vergleich. physiol. Vortrage," 1886, S. 314. 
11 Ztschr. f. Chem., Strassburg, 1890, Bd. xiv. S. 576; Krukenberg, Cemtralbl. 
f. d. med. W .. Berlin, 1887, No. 25. 
'- Arch.f. d. i/rs. Ph : /sin T . , Bonn. lM>5.Bd.lxii.S. 332. Fortbe metbodemployed,see?M2.,S.l. 
13 Arch, de physiol. 'norm, etpath., Paris, Ser. 5, tome vi. 
