MUSCLES. 



59 



37. Unstriped muscle is, for the most part, found diffused 

 among the other tissues of organs, into the formation of which 

 it enters, or lying in strata. Striped muscle, for the most 

 part, is gathered into definitely limited organs called muscles, 

 which have a distinct origin and insertion, and usually a 

 certain amount of tendon in their construction. The extent 

 of action of a muscle depends on the length of its fibres, 

 while its strength of action is in proportion to the number of 

 them. When therefore a muscle consists 

 of few fibres running lengthwise from origin 

 to insertion, it is useful rather for the extent 

 of the movement which it serves, than for 

 the force which it gives to it. But when 

 great resisting power is required in a muscle, 

 its tendons extend through its substance, and 

 its muscular fibres are short and numerous, 

 passing obliquely from one prolongation of 

 tendon to another: thus in the soleus, one 

 of the muscles of the calf already referred 

 to (p. 51), the fibres are arranged in four 

 oblique sets, and are none of them more than 

 about an inch in length; so that the muscle 

 is incapable of approximating its attach- 

 ments more than an inch, but can exert in 

 its limited range an enormous force, and is 

 thus well adapted to sustain the weight of 

 the body in standing. 



Fig. 32. Deep 

 surface of so- 

 leus muscle. 



