AND ANIMAL LIFE. 211 



seven cervical, the twelve dorsal, the five lumbar, 

 and the six sacral. They are common to all ani- 

 mals, from the worm up to man, and are for the 

 purposes of common sensation and motion, or acts 

 of volition."* This discovery enables us to cul- 

 tivate an intimate acquaintance with the consti- 

 tution of the nerves belonging to the thoracic 

 and abdominal cavities, to note with precision 

 their origin, their compound nature, and to un- 

 derstand the character of those endowments 

 which they bestow on the different viscera on 

 which they are distributed. 



CCXXXV. If we believe, with some anato- 

 mists, that the sympathetic nerve is derived from 

 the fifth and sixth, we shall be enabled to speak 

 with confidence of its properties ; or if we grant 

 that it is merely connected with these nerves, we 

 are still able to discriminate its functions, by ob- 

 serving the office of those organs and muscles 

 to which it is distributed, and by noting the con- 

 sequences which follow its partial destruction, or 

 the phenomena which it exhibits on the applica- 

 tion of galvanism. 



The par vagum is evidently a nerve of respira- 

 tory motion; the branch of the fifth and that of the 

 sixth, which form the whole, or constitute a part of 

 the sympathetic, transmit motion or sensibility ; 

 and the whole of the spinal nerves are proved to 



* Ibid. p. 44. 



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