466 MOVEMENTS VOICE AND SPEECH. 



tary. Peristaltic action is the rule, and the contraction takes place progress- 

 ively and without oscillations. Contractility persists for a long time after 

 death. Excitation of the nerves has less influence upon contraction of these 

 fibres than direct excitation of the muscles. The involuntary muscular tis- 

 sue is regenerated very rapidly, while the structure of the voluntary muscles 

 is restored with great difficulty after destruction or division (Legros and Oni- 

 mus). 



Physiological Anatomy of the Voluntary Muscular Tissue. A voluntary 

 muscle contains, in addition to its peculiar contractile substance, fibres of in- 

 elastic and elastic tissue, adipose tissue, abundant blood-vessels, nerves and 

 lymphatics, with certain nuclear and cellular anatomical elements. The 

 muscular system in a well proportioned man is equal to about two-fifths of the 

 weight of the body (Sappey). Its nutrition consumes a large proportion of 

 the reparative material of the blood, while its disassimilation furnishes a cor- 

 responding quantity of excrementitious matter. The condition of the mus- 

 cular 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 contract- 

 ing forcibly on the reception of a proper stimulus, and a peculiar kind of 

 sensibility. The relations of particular muscles, as taught by descriptive anat- 

 omy, involve special acts ; but the most important physiological points con- 

 nected with this system relate to the general properties and uses of the mus- 

 cles. 



The voluntary muscles are made up of a great number of microscopic 

 fibres, known as the primitive muscular fasciculi. These are called red, stri- 

 ated or voluntary fibres. Their structure is complex, and they may be sub- 

 divided longitudinally into fibrillae and transversely into disks. In very short 

 muscles, some of the primitive fasciculi may run the entire length of the 

 muscle; but the fasciculi usually are 1-2 to 1-6 inch (30 to 40 mm.) in 

 length. The fasciculi, however, do not inosculate with each other, but the 

 end of one fasciculus is united longitudinally with the end of another by a 

 strongly adhesive substance, the line of union being oblique ; so that the fibres 

 practically run the entire length of the muscle. Each fasciculus is enclosed in 

 its own sheath, without branching or inosculation. This sheath contains 

 the true muscular substance only, and it is not penetrated by blood-vessels, 

 nerves or lymphatics. In a thin, transverse section of a muscle, the divided 

 ends of the fibres present an irregularly polygonal form with rounded cor- 

 ners. They seem to be cylindrical, however, when viewed in their length and 

 isolated. Their color by transmitted light is a delicate amber, resembling 

 the color of the blood-corpuscles. 



The primitive fasciculi vary very much in size in different individuals, in 

 the same individual under different conditions, and in different muscles. As 

 a rule they are smaller in young persons and in females than in adult males. 

 They are comparatively small in persons of slight muscular development. 

 In persons of great muscular vigor, or when the general muscular system or 



