NORMAL AXD ABNORMAL MOVEMENTS. 



133 



Fig. 26. 



seated upon a chair and told to rise at a given signal. His right 

 hand was resting on the chair just where the arched -piece of the 

 back is joined to the seat. 

 When everything was in 

 readiness he was told to 

 rise. The tremor which 

 had been marked while 

 the hand was resting on 

 the chair gradually be- 

 came less and less evident, 

 and finally ceased when the 

 erect position was reached. 



In Fig. 26 the lower 

 row of dots is seen to be 

 double at the beginning of 

 the act, thus showing the 

 presence of tremor. As 



the man approaches the erect position the dots are gradually less 

 widely separated and finally coalesce. In the case of the elbow, 

 and also of the shoulder, a single continuous row of dots alone is 

 seen. 



From the above figures it is very evident that a properly con- 

 structed " Marey wheel" offers a valuable and accurate method of 

 studying not only tremors but probably also other forms of abnor- 

 mal movement. 



The man is in tlie act of rising and walking forward. 

 A bright button is fixed upon the hand. The double 

 row of dots indicate the tremor of the hand. 



ADDENDUM. 



In Mr. Muybridge's catalogue a number of the clinical plates are incor- 

 rectly designated. 



Plate 549 should be " Locomotor Ataxia." 

 Plate 555 should be " Muscular Atrophy of Left Leg." 

 Plate 558 should be " Stuporous Melancholia." 

 Plate 559 should be " Partial Paraplegia." 



