94 ANALYTIC SECT. X. 
restored through all its ramifications; the in- 
creased arterial expansibility is here local, being 
confined to one arm. If the vital force in a case 
of intermittent fever, be raised generally, an hour 
or two before the accession of the cold stage, by 
applying lunar caustic to the spine, the whole 
arterial system retains at least its natural expan- 
sibility. These facts must convince every unpre- 
judiced and reflecting mind, that the vital force 
contributes materially to the expansibility of the 
arterial system; but what portion of it belongs 
to the force of the heart, and mechanical disten- 
tion by the blood, and what to the vital force, it 
is impossible to ascertain—calculation is not appli- 
cable to the laws of vitality. | 
ccxvul. The influence of the mind on various 
parts of the arterial system, is a further proof of 
the dependance of its irritability on the vital 
force. 'The pudic arteries may be thrown into 
violent action solely .by the imagination, and 
every one has observed the effects of fear and 
shame on the colour of the cheeks. Violent 
emotions of the mind, which raise the vital force, 
have sometimes even arrested the cold stage of 
an intermittent fever. Pliny mentions the case 
of a Roman consul, who was radically cured of 
an ague, by fighting a battle on the day of its 
accession. Sometimes even general expansion of 


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