AND ANIMAL LIFE. 305 



CCCXXXVII. The muscles of the arm be- 

 come weak if long exerted, or if put into an un- 

 natural position ; but it is not the province of 

 these muscles to dilate and contract upon their 

 contents, in order to propel the blood regularly 

 to other organs ; alternate rest and activity are 

 necessary for their office. The heart is the cen- 

 tre of circulation, and the dependence of every 

 function on its unceasing action would seem to 

 imply, that activity alone is the condition in which 

 it can be invigorated ; and it is also found from 

 experience, that almost every cause, whether con- 

 tinued or occasional, which augments its impulse 

 increases its muscular development. 



CCCXXXVII I. The heart, in a paroxysm of 

 syncope, is sometimes instantaneously arrested in 

 its motion. When this is the case, we cannot con- 

 sistently say that it is weakened, because it has 

 not been over excited, nor have we a right to sup- 

 pose that it is recruiting its nervous energy dur- 

 ing the state of quiescence. 



CCCXXXIX. The general symptoms which 

 precede and characterize syncope are in the greater 

 number of instances the same, but the extent 

 and variety of these are occasionally much modi- 

 fied by the severity and suddenness of the fit. If 

 the symptoms are gradual in their progress, we 

 have nausea, vertigo, pain in the epigastric re- 

 gion, sensation of cold, tremors of the extremi- 

 ties, paleness of the countenance, lividness and 



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