110 PHYSICAL EXPKESSION. 



as to the symptoms that result from lesion of cer- 

 tain portions of the brain. This encourages us to 

 observe, in all cases of health and disease, the move- 

 ments and results of movement, knowing that these 

 correspond to, and are the direct outcome of, the 

 states of certain nerve-centres. The knowledge 

 that we already possess of the nerve-centres is from 

 observation of muscular action. In a given case, 

 by comparing the state of the muscles during life, as 

 they may be affected by paralysis or spasm, with 

 the brain lesion found after death, and by collecting 

 and comparing many cases, it has been found that 

 destructive or irritative lesions of certain parts of 

 the brain cause paralysis or spasm of a certain set 

 of muscles corresponding. 



Epilepsy is a chronic disease, characterized by 

 (1) attacks of more or less disturbance of con- 

 sciousness, (2) muscular spasms and convulsions. 

 The careful, detailed, and accurate observation and 

 record of the movements of the convulsion, and 

 sequent paralyses, has proved an efficient means of 

 study in this disease, the movements and results of 

 movements being studied as indices of the action of 

 nerve-centres. Epilepsy is a condition of disease of 

 which we know but little beyond what can be learnt 

 from studying nerve-muscular movements, and their 

 associations and concomitants; still we do possess 

 much practical and useful knowledge of epilepsy. 



Chorea is a disease, or abnormal condition, com- 

 monly seen in children. It is characterized by a 

 great excess of involuntary movement, and a vary- 

 ing amount of muscular weakness. The movements 



