78 OE THE MUSCLES. 



would have swelled that part to an awkward and clumsy 

 thickness. The beauty, the proportions of the part, would 

 have been destroyed. They are therefore disposed in the 

 arm, and even up to the elbow ; and act by long tendons, 

 strapped down at the wrist, and passing under the ligament 

 to the fingers, and to the joints of the fingers, which they 

 are severally to move. (PI. XIII. fig. 1, 2.) In like man- 

 ner, the muscles which move the toes, and many of the 

 joints of the foot, how gracefully are they disposed in the 

 calf of the leg, instead of forming an unwieldly tumefaction 

 in the foot itself? The observation may be repeated of the 

 muscle which draws the nictitating membrane over the eye. 

 Its ofiice is in the front of the eye ; but its body is lodged 

 in the back part of the globe, where it lies safe, and where 

 it encumbers nothing.* 



V. The great mechanical variety in the figure of the 

 muscles may be thus stated. It appears to be a fixed law, 

 that the contraction of a muscle shall be towards its centre. 

 Therefore the subject for mechanism on each occasion is, 

 so to modify the figure, and adjust the position, of the mus- 

 cle, as to produce the motion required agreeably with this 

 law. This can only be done by giving to different muscles, 

 a diversity of configuration, suited to their several offices, 

 and to their situation with respect to the work which they 

 have to perform. On vrhich account we find them under 

 a multiplicity of forms and attitudes ; sometimes with 

 double, sometimes with treble tendons, sometimes with 

 none ; sometimes one tendon to several muscles, at other 

 times one muscle to several tendons. The shape of the 

 organ is susceptible of an incalculable variety, whilst the 

 original property of the muscle, the law and line of its con- 

 traction, remains the same ; and is simple. Herein the 

 muscular system may be said to bear a perfect resemblance 

 to our works of art. An artist does not alter the native 

 quality of his materials, or their laws of action. He takes 



* The convenience and beauty of the tendons seem only an ulterior 

 object, their necessity and utility principally claim our attention. The 

 force which a muscle possesses is as the number of the muscular fi- 

 bres ; but a limited number of fibres only can be fixed to any certain 

 point of bone destined to be moved, therefore the contrivance is, to 

 attach them to a cord, called a sinew or tendon, which can be conve- 

 niently conducted and fixed to the bone. If we are desirous of mov- 

 ing a heavy weight, we tie a strong cord to it, that a greater number 

 of men may apply their strength. Thus a similar effect is produced — 

 the muscular fibres are the moving powers, the tendons are the cords 

 attached to the point to be moved. Paxton. 



