NORMAL AND ABNORMAL, MOVEMENTS. 



127 



and which is present only under certain conditions. Thus, when 

 Mr. C. is sitting or standing still, the arm is carried in a serai- 

 flexed position, while the hand and fingers are markedly con- 

 tracted and in constant vibration. Were it not for this last factor 

 — namely, the vibration — the position would bear some resem- 

 blance to that assumed by patients suffering from secondary con- 

 tracture. 



If Mr. C, however, attempts to rise or to walk, the forearm 

 becomes slightly less flexed, whilst the vibration increases both in 

 amplitude and rapidity. If the walk be persisted in, and be it 



Fig. 20. 



Fig. 19. 



ever so slow and gentle, the forearm finally becomes completely 

 extended, and now the entire arm describes a rotary motion, such 

 as is depicted in the upper series of Plate 557, and in Fig. 19. 



It will be observed that this movement is one in which the 

 band, while it is suspended from the shoulder like a pendulum, de- 

 scribes a circle by first sweeping forward, then outward, then back- 

 ward, and, finally, forward again to its original position. Fig, 19 

 illustrates the extent of this movement in the outward direction. 



If, now, while the arm is performing this peculiar movement, 

 Mr. C. attempts to raise the arm up to the shoulder, the rotary 

 movement increases wonderfully in extent. {Vide Plate 557, 

 middle series.) The arm describes a circle, indicated by the 



