82 



ANIMAL MECHANICS 



origin to insertion, but obliquely, thus, from 

 tendon to tendon : 



FIG. 25. 



Supposing the point A to be the fixed point, 

 these fibres draw the point B with less force, but 

 through a larger space, or more quickly than if 

 they took their course in direct lines ; and by this 

 arrangement of the fibres the freedom and extent 

 of motion in our limbs are secured. 



But the muscles must be strengthened by addi- 

 tional courses of fibres, because they are oblique ; 

 since by their obliquity they lose something of 

 their force of action : and therefore it is, we must 

 presume, that we find them in a double row, mak- 

 ing what is termed the penniform muscle, thus, 



and sometimes the 

 texture of the mus- 

 cle is still further 

 compounded by the 

 intermixture of ten- 

 dons, which permit additional series of fibres ; and 

 all this for the obvious purpose of accumulating 

 power, which may be exchanged for velocity of 

 movement. 



We may perceive the same effect to result from 

 the course of the tendons, and their confinement 



FIG. 26. 



