THE MUSCLES. 91 



niLinicate with the point of action by slender strings or wires. 

 If the muscles which move the fingers had been placed in 

 the palm or back of the hand, they 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 ligaments to the fingers,* and to the 

 joints of the fingers which they are severally to move. In 

 like manner, 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 unv/ieldy tumefaction 

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

 muscle which draws the nictitating membrane over the eye. 

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

 the back part of the globe, v/here it hes 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 muscle as 

 to produce the motion required agreeably Avith this law. 

 This can only be done by giving to different muscles a diver- 

 sity of configuration suited to their several offices, and to 

 their situation with respect to the work which they have to 

 perform. On which account we find them under a multi- 

 plicity of forms and attitudes : sometimes with double, some- 

 times with treble tendons, sometimes with none ; sometimes 

 one tendon to several muscles, at other times one muscle to 

 several tendons. f The shape of the organ is susceptible oi 



* See Fig. 2, where e is the annular ligament of the wrist, u.ndejf 

 which pass the tendons of the muscles of the fingers. 



t Plate III., Fig. 3, represents the biceps muscle of the arm ; a, 

 a, tne tendons ; h, b, the muscular fibres. The force which a muscle 

 poi^-esses is as the number of the muscular fibres ; but a limited nusa- 



