CHAPTER XI. 

 MUSCLES. 



STRIATED MUSCLES. 



IN the study of the muscles the chief problem for physiological chem- 

 istry is to isolate their different morphological elements and to investigate 

 each element separately. By reason of the complicated structure of 

 the muscles this has been thus far almost impossible, and we must bo 

 satisfied at the present time with a few microchemical reactions in the 

 investigation of the chemical composition of the muscular fibres. 



Each muscle-tube and each muscle-fibre consists of a sheath, the 

 SARCOLEMMA, which seems to be composed of a substance similar to 

 elastin, and containing a large proportion of protein. This last, which 

 in life posesses the power of contractility, has in the inactive 

 muscle an alkaline reaction, or, more correctly speaking, an amphoteric 

 reaction with a predominating action on red litmus paper. ROHM ANN 

 found that the fresh, inactive muscle shows an alkaline reaction with 

 red lacmoid, and an acid reaction with brown turmeric. From the 

 effect of various acids and salts on these coloring-matters he concludes 

 that the alkalinity of the fresh muscle with lacmoid is due to sodium 

 bicarbonate, diphosphate, and probably also to an alkaline combination 

 of protein bodies, and the acid reaction with turmeric, on the contrary, 

 to monophosphate chiefly. The dead muscle has an acid reaction, or, 

 more correctly, the acidity with turmeric increases on the decease of the 

 muscle, and the alkalinity with lacmoid decreases. The difference 

 depends on the presence of a larger quantity of monophosphate in the 

 dead muscle, and according to ROHMANN free lactic acid is found in 

 neither the one case nor the other. 1 



If the somewhat disputed statements relative to the finer structure 

 of the muscles are disregarded, one can differentiate in the striated 

 muscles between the two chief components, the doubly refracting 

 anisotropous and the singly refracting isotropous substance. If the 

 muscular fibres are treated with reagents which dissolve proteins, 



1 The various reports in regard to the reaction of the muscles and the cause 

 thereof are conflicting. See Rohmann, Pfliiger's Arch., 50 and 55; Heffter, Arch. f. 

 exp. Path. u. Pharm., 31 and 38. These references contain the pertinent literature. 



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