VOLUNTARY MUSCLES. 4:49 



tractility persists for a long time after death. Arrest of 

 function is followed by little or no atrophy, and hyper- 

 trophy is very marked as the result of exaggerated action. 

 Excitation of the nerves has less influence upon contraction 

 of these fibres than direct excitation of the muscles. The 

 involuntary muscular tissue is regenerated very rapidly, 

 while the structure of the voluntary muscles is restored with 

 great difficulty after destruction or division. 1 



Physiological Anatomy of the Voluntary Muscles. A 

 voluntary muscle is the most highly organized, and is 

 possessed of the most varied endowments, of all living 

 structures. It contains, in addition to its own peculiar 

 contractile substance, fibres of inelastic and elastic tissue, 

 adipose tissue, numerous blood-vessels, nerves, and lym- 

 phatics, with certain nuclear and cellular anatomical ele- 

 ments. The muscular system constitutes by far the greatest 

 part of the organism, and its nutrition consumes a large pro- 

 portion of the reparative material of the blood, while its 

 clisassimilation furnishes a corresponding quantity. of excre- 

 mentitious matter. The condition of the muscular system, 

 indeed, is an almost unfailing evidence of the general state 

 of the body, allowing, of course, for peculiarities in different 

 individuals. Among the characteristic properties of the 

 muscles are, elasticity, a constant and insensible tendency to 

 contraction, called tonicity, the power of contracting forci- 

 bly on the reception of a proper stimulus, called irritability, 

 a peculiar kind of sensibility, and the faculty of generating 

 galvanic currents. The relations of particular muscles, as 

 taught by descriptive anatomy, involve special functions ; 

 but the most interesting physiological points connected with 

 this system relate to the general properties and functions of 

 the muscles, and must necessarily be prefaced with a sketch 

 of their general anatomy. 



1 LEGROS ET OXIMUS, De la contraction des muscles de la vie vegetative. Jour' 

 nal de Tanaiomie, Paris, 1869, tome vi., p. 435. 

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