240 



PHYSIOLOGICAL CHEMISTRY. 



and nonstriated muscle and of blood serum for comparison is shown 

 in the appended table : 



Muscular tissue is said to contain a reddish pigment called myo- 

 hcematin, which is a derivative of haemoglobin. 



The so-called " fatigue substances "of muscle are carbon diox- 

 ide, paralactic acid and potassium dihydrogen phosphate. 



The ordinary commercial "meat extract" is composed princi- 

 pally of the water-soluble constituents of muscle and contains practi-. 

 cally nothing of nutritive value. The protein material to which 

 meat owes its value as an article of diet is practically all removed 

 in the preparation of the extract. 



The structural formulas of the nitrogenous extractives of muscle 

 are as follows : 



NIL 



=$ 



HN 



CREATINE, C4H 9 



Methyl-guanidine acetic acid. 



HN 



HN- 



4 



-CO 



CH ft -CH*COOH 



NH 2 



C = 







UREA, CON 2 H 4 . 



(CH 3 ) 3 -N 



/ 



\ 



0- 



CH 3 -CH 2 



CREATININE, C4H 7 N 3 O. 

 Creatine anhydride. 



CH 2 -NH 2 



CH 2 -S0 2 OH 



TAURINE, C 2 H 7 NSO 3 . 

 Amino-ethyl-sulphonic acid. 



CO 



CTL-CH-OH-CH., 



CARNITIME, 

 'y-trimethyloxybutyrobetaine. 



Carnosine, C 9 H 14 N 4 3 . 





