256 PHYSIOLOGICAL CHEMISTRY. 



Muscle-syntonin, which may be obtained by extracting the 

 muscles with hydrochloric acid of 1 p. m., and which, according to 

 K. MORNER, is less soluble and has a greater aptitude to precipitate 

 than other acid albumins, seems not to occur pre-existent in the 

 muscles. 



Muscle-coloring Matters. There is no question that the red 

 color of the muscles even when completely freed from blood de- 

 pends in part on haemoglobin, though it is contested by many. 

 MAcMuNtf claims that the muscles contain also another coloring 

 substance which is nearly related to the blood-coloring matters and 

 whose spectrum is very similar to that of haemochromogen. This 

 coloring matter has been called myoJicematin. According to LEVY 

 and HOPPE-SEYLER, this myohaematin is nothing but haemochromo- 

 gen, which is produced from oxyhaemoglobin by decomposition 

 and reduction. Nevertheless MAcMuNN still adheres to his view 

 that myohsematin is an independent coloring substance, and in sup- 

 port of his opinion he adduces the fact that inyohaematin is found 

 also in the muscles of insects in which no haemoglobin occurs. 



The reddish-yellow coloring matter of the muscles of the salmon has been 

 little studied. Traces of enzymes, such as pepsin and diastatic enzymes, have 

 been found in them. The so-called " myosin-ferment," and probably an 

 enzyme producing lactic-acid fermentation, are also found in these muscles. 



Extractive Bodies of the Muscles. 



The nitrogenized extractives consist chiefly of creatin, in the 

 proportion of 2-4 p. m., in the fresh muscles containing water, alj/o 

 the xanthin bodies, hypoxanthin and xanthin, besides guanin and 

 carnin. The average quantity of hypoxanthin, xanthin, and guanin 

 in 1000 parts of the dried substance of the muscles of oxen is, 

 according to KOSSEL, respectively 2.30, 0.53, and 0.20 grms., and in 

 the embryonic ox-muscles respectively 3.59, 1.11, and 4.12 grms. 



Besides these we must also consider as an extractive body the syrupy inosic 

 acid (CioHi 4 N 4 Oii), of which only traces are found in certain animals. This 

 acid was first prepared by LIEBIG, but not closely studied. LIMPRICHT has 

 found another in the flesh of certain cyprindea, namely, the nitrogenized pro** 

 acid. Uric acid, urea, taurin, and leucin are found as traces in the muscles in 

 certain cases only, in a few species of animals. In regard to the amount of 

 these different extractives in the muscles, KRUKENBERG and WAGNER have 

 shown that it varies greatly in different animals. A large amount of urea is 

 found in the muscles of the shark and ray ; uric acid is found in alligators ; 



