WALKING. 63 



Weber, represents a pendulum which bends and oscillates 

 by its weight alone; according to M. Duchenne (of Bou- 

 logne), it obeys the contraction of the flexor-muscles. 



The experiments of the Webers having demonstrated, 

 as stated above, that the head of the femur is retained 

 in the cotyloid cavity by atmospheric pressure alone, these 

 skilful observers conclude that in the second movement in 

 walking the weight of the thigh alone determines the flexion 

 of the joints and the oscillation of the three segments of the 

 pendulum, which is then represented by the lower extremity. 

 Basing his opinion on pathological observation, M. Duchenne 

 thinks that the contraction of the flexors of the thigh, leg, 

 and foot is the real cause of the second movement of the 

 extremity in walking, and that the action of weight contri- 

 butes very little to it. According to M. Beclard, the tonicity 

 of the flexor-muscles, developed by extension, suffices for 

 seconding the pendulum movement of the lower limb. 



In walking the body advances without ceasing to rest 

 upon the ground, and by effecting a succession of move- 

 ments, which are divided in each step into two principal 

 ones. First, the body rests upon the two lower limbs ; the 

 right leg, placed behind and inclined to the horizon, touches 

 the ground at the extremity of the metatarsus and at the 

 toes, it stretches out, and the foot is raised to an angle of 

 forty-five degrees; now the left limb is placed forward, rest- 

 ing on the ground on its sole, the knee is a little bent, the 

 heel exactly under the head of the femur, and the trunk 

 slightly inclined forward. Secondly, the left leg alone sup- 

 ports the weight of the body; it lengthens by extending the 

 knee and straightening the foot; its direction inclines to the 

 horizon, and the body pushes itself forward, while the right 

 leg is raised from the ground by bending the knee, follows 

 the movement of translation given to the body, executes 

 half an oscillation, and touches the ground, first at the heel, 

 which places itself exactly under the head of the femur, and 

 then on the sole of the foot on which the body rests. 



To accelerate his movement man inclines more forward, 

 the centre of gravity falls nearer to the earth, and the flexion 

 of the limb placed behind is greater, the pendulum is shorter 



