CHAPTER XVI. 



THE MUSCLE-TISSUE. 



I HAVE pointed out that while in the monocellular organisms the 

 various functions of the body are carried on by the single cell, a 

 gradual division of labor occurs as we ascend in the scale of both 

 animal and vegetable life, where groups of cells are set aside for the 

 performance of certain special functions. Structurally this division 

 of labor finds its expression in a more or less well-marked deviation 

 from the original type, as has been shown. At first sight, it is 

 thus difficult to connect the highly differentiated muscle-cell with 

 the apparently much more simple ovum from which it has originated. 

 The element of reproduction and secretion is here manifestly placed 

 in the background, while in its co-ordinate and rapid contraction on 

 stimulation we have abundant evidence of its highly specialized 

 function. That this should further be expressed in the chemical 

 composition of the cells suggests itself at once. As a matter of 

 fact, we here find substances which may be regarded as specific 

 muscle components, and it seems warrantable to assume that a 

 definite connection exists between these bodies and the special func- 

 tion of the cell. On chemical examination we may then further 

 expect to meet with the various products of katabolism, so far as 

 these are found in the muscle-tissue proper, and have not as yet been 

 removed by the blood or the lymph. 



Before proceeding to a study of these various substances in detail, 

 a few analyses of muscle-tissue are here introduced, which will 

 furnish a general idea of its chemical composition. Qualitatively 

 this is fairly constant, but quantitative variations occur which are 

 often very marked. 



In preparing the tissue for analytical purposes, the blood should 

 first be washed out entirely with dilute saline solution (0.6 per cent.). 

 Fibrous tissue and fat must be dissected away as far as possible and 

 all larger bloodvessels removed. The material is then further 

 scraped, so as to get rid of as much of the connective tissue as pos- 

 sible which binds the individual fibres together, and is now ready 

 for examination. 



Analyses of Fresh Muscle -tissue (Neumeister). The figures 

 represent average values, which have been collected from various 

 sources, and have reference to mammalian muscle-tissue in general, 

 unless otherwise stated. 



