PARALYSIS AGITANS. 431 



A hypochondriac merchant, while sawing wood, is always busy with 

 the thought that he is sawing wood because he is sick. Such ordi- 

 nances, however, especially active gymnastic exercise, are of great 

 service, because, like the cold baths, they induce a vigorous modifi- 

 cation in the process of transmutation of the tissues, and because 

 they tend to restore the patient to a sense of physical energy. 

 Diverting amusements, as the excitement which they produce soon 

 becomes extinct, are seldom productive of lasting benefit. Travel- 

 ling with some definite object in view, or the study of agreeable 

 objects, is much more commendable. Of course, no general rules 

 can be laid down for the fulfilment of the task in question, as our 

 directions must always be in accordance with the capacity, educa- 

 tion, and means of the patient. 



[CHAPTER VIII. 



PAEALYSIS AGITANS SHAKING PALSY. 



THE most apparent symptoms of this disease are involuntary 

 movements of parts of the body, either a simple trembling or a 

 regular shaking ; sooner or later these are accompanied by partial 

 paralysis of the muscles affected. The disease is uncommon ; it 

 affects chiefly aged men; exceptionally it occurs in middle age, and 

 very rarely in youth. In some cases it has followed severe fright 

 or great anxiety ; in others it has seemed due to unfavorable sur- 

 roundings, exhausting work, continued exposure to moisture and 

 cold, or to irritation of peripheral nerves from injury ; in other cases 

 no external cause has been found. 



The trembling usually begins in the fingers, hands, or arms, and 

 may remain limited there, or may spread to the whole upper or 

 lower limbs ; exceptionally it affects the muscles of the face, larynx, 

 or neck. The tremor may be restricted to the limbs of one side of 

 the body, rarely to one arm and the opposite leg. The movements 

 may cease temporarily, especially in the horizontal position ; but 

 when fully developed it is apt to be continuous, though varying in 

 intensity from mental or physical excitement ; during sleep or an- 

 aesthesia the movements cease. 



The paralysis may not come on for some time, the impaired use 

 of the limbs meantime being due to disturbance from the motion. 

 Late in the disease there may be a tenseness and rigidity of the 

 muscles, with preponderance for the flexors ; after the tenseness 

 has lasted some time it will cause deformity ; the head may be 



