MUSCULAR TISSUE. 



239 



contain xanthine. It has been found unaccompanied by xanthine, 

 in bone marrow and in milk. Unlike xanthine it may be easily 

 crystallized in the form of small, colorless needles. It is readily 

 soluble in alkalis, acids and boiling water, less soluble in cold water 

 and practically insoluble in alcohol and ether. 



The predominating inorganic salt of muscle is potassium phos- 

 phate. Besides this salt we have present chlorides and salts of 

 sodium, calcium, magnesium and iron. Sulphates are also present 

 in traces. 



Mendel and Saiki have recently made some interesting observa- 

 tions upon the chemical composition of nonstriated (involuntary) 

 mammalian muscle, such as the urinary bladder and the muscular 

 coat of the stomach of the pig. Hypoxanthine was found to be 

 the predominant purine base present. Creatine and paralactic acid 

 were also isolated. These investigators were unable to demonstrate, 

 definitely, the presence of glycogen in the nonstriated muscles 

 studied, but state that "the tissues possess the property of trans- 



FIG. 78. 



XANTHINE. 



After tne drawings of Horbaczewski, as represented in Neubauer and Vogel. 



(Ogden.) 



forming glycogen in the characteristic enzymatic way." The most 

 important part of their investigation consists in a rather complete 

 analysis of the inorganic constituents of these muscles. A notable 

 difference in the relative distribution of the various inorganic con- 

 stituents was observed, a difference which, according to the authors, 

 "can be accounted for in part only by an admixture of lymph." 

 The comparative composition of the inorganic portion of striated 



