NORMAL AND ABNORMAL MOVEMENTS. 



107 



In Fig. 1, the line a rep- 

 resents the rise and fall and 

 onward movement of the 

 white button in the cap 

 worn by the subject, while 

 the line b represents the 

 amount and direction of 

 its lateral sway. As in 

 the trajectory of the pubis 

 determined by Marey, the 

 number of vertical oscilla- 

 tions appear to be double 

 those which take place in a 

 horizontal direction. 



In Fig. 2, the rise and 

 fall of the right superior 

 spinous process of the ilium 

 is represented in the line e. 

 It is similar in general 

 course to the line «, but 

 the amplitude of the wave 

 is much greater. This 

 increase in amplitude is 

 doubtless in part due to 

 the meagre lateral oscilla- 

 tion of the ilium during 

 the time the right foot is 

 fixed upon the ground. In 

 fact, in the line (] the 

 amount of curve is ex- 

 ceedingly small, — i.e., dur- 

 ing the time the ilium is 

 describing the arc xy (line 



In Fig. 3, the line e rep- 

 resents the rise and fall 

 and forward movement of 

 the left foot, the internal 

 malleolus being; taken as a 



Fig. 3. 



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