LAWS OF BONE ARCHITECTURE 219 



original researches firmly established the mechanism of muscle 

 action upon a firm scientific foundation. Improvements in the 

 methods of study have been produced by the extended use of 

 graphics and the development of instantaneous photography. 

 Carlet (72) and Marey ('72) developed graphic methods of 

 great value and the study of successive phases of movements in 

 man by instantaneous photography, first applied by Muy- 

 bridge ('87), and later by Marey ('94) and others, have pro- 

 duced very valuable results in the study of human locomotion. 



The Webers have sho\Mi that in both walking and running the 

 body is thrown foiward by rhythmic and alternating muscle con- 

 tractions, chiefly of the lower limbs. In walking one foot is 

 always in contact with the ground, but in running after one foot 

 has touched the ground the body is projected into the air for 

 a brief interval and the succeeding contact with the ground is 

 made with the other foot. 



In walking the step begins with placing the foot on the ground, 

 the foot and the knee being in moderate flexion, the weight of 

 the body falls on the heel of the forward foot and at the same 

 instant the great toe of the other foot is in contact with the 

 ground. At the next instant, through the action of the muscles 

 of the lower leg additional pressure is applied through the 

 great toe of the foot behind and the body is thrust forward. 

 Then the foot behind is drawn forward and flexed simultaneously 

 and swung forward to pass the loaded foot. Just as the swing- 

 ing foot passes the loaded foot the weight of the body is trans- 

 ferred to the ball of the foot and just before the swinging foot 

 touches the ground the weight on the loaded foot is transferred 

 to the great toe. As the forward foot strikes the ground the 

 weight of the body is borne by the great toe of the rear foot and 

 the heel of the forward foot, and a sudden thrust from the great 

 toe propels the body forward and the rear foot rises from the 

 ground. The greatest pressure on the ground occurs when the 

 thmst is given by the great toe of the rear foot, and the amount 

 of this maximum pressure as determined by Carlet with ex- 

 ploring shoes which comnmnicate the pressure on the foot through 

 tambours, which automatically recorded the pressures, is a little 



