132 A STUDY OF SOME 



and with apparent difficulty. The first line above the heavy 

 white stripe is almost in contact with the latter, and cannot be 

 seen except upon close inspection. Thence the intervals between 

 the various lines gradually increase until towards the completion 

 of the movement, when they again ai)pear to diminish. Though 

 this increase of rapidity of movement and subsequent decrease is 

 the same in principle as that which takes place normally, still the 

 slowness of the start and the slowness of the entire movement 

 are remarkable. For instance, the arm sweeps over thirteen in- 

 tervals before the stripe touches the chin and nose, — that is, 

 counting up to the upper impression of the face, as during the 

 movement the patient threw her head and shoulders backward. 

 The thirteen intervals correspond to ^, or about two-thirds of a 

 second. Therefore it took the patient all of this time to move her 

 hand up to a level of the face, although she was told to move as 

 quickly as possible. 



No tremor is noticed in the leg or foot. In Fig. 25 the arm 

 and foot were also raised at the same time and then brought 

 down again. No tremor is noticed in the foot, but both in the 

 ascent and descent of the arm the double rows of dots are plainly 

 seen. 



This persistence of the tremor of paralysis agitans during vol- 

 untary movement is a matter of considerable importance from 

 the diagnostic point of view. It is generally accepted that one of 

 the chief diagnostic features of the disease is the cessation of 

 the tremor during voluntary movement. This was certainly the 

 case when the patient was first seen, but as the disease progressed 

 the cessation no longer took place, and this is proven by the 

 photograph. 



The other case, photographed by means of the " Marey wheel," 

 was a man, aged sixty-five, who had been incapacitated from work 

 for about seven months by reason of a tremor of the right hand. 

 The case appeared to be one of commencing paralysis agitans, 

 although some of the symptoms, such as rigidity and festination, 

 were not typical. 



The photograph of Fig. 26 was made in exactly the same 

 manner as the preceding ones, with the exception that the patient 

 wore the white stripe upon the arm only. Tiiere was a metallic 

 button on the shoulder, at the elbow, and on the hand. He was 



