222 On the Vital Principle. 



quenCe of a certain organization*. But while no 

 fingle hypothefis refpeding the vital principle 

 p^-evailed generally, two theories appeared, which 

 engaged attention by the enninence of their au- 

 thors, as well as by their own nature. Dr. 

 Monro accounts for the commencement of tlie 

 involuntary motions, and fome other phasnomena, 

 on the fuppofition of a living principle, perva- 

 ding the univerfef; fimilar, I apprehend, to the 

 plaftic nature of the Platonifts. Mr. Hunter 

 attributes to the blood, a power of forming and 

 renewing parts, by its proper efforts, apparently 

 carried, in fome cafes, almoft to a degree of 

 rationality:}:. It is fufficient to prove the great 

 differences among modern phyfiologifts, on this 

 fubjedl, to obferve, that while Dr. Hoffman has 

 diftinguifhed, in very ftrong terms, between the 

 fenfitive and rational fouls |1, Dr. Cullen allows, 



that 



* HofFman, T. I p. 18. BufFon, Hiltoire Naturelle 

 Since this Effay was written, Dr. Fordyce has attempted 

 to account for mufcular motion on the theory ojT a peculiar 

 attraftion, which he terms the attraifion of life. But, as 

 I had occafion to obferve elfewhere, there is too much 

 defign in mufcular aftion to be mechanically explained, 

 nor would our perplexity be at all diminiflied, by receiving 

 an explanation which is fully as obfcure as the caufe of the 

 phenomena to which it relates. 



f Obfcrv. on the Nervous Syftem, p. ult. 

 X Med. Commentaries, vol. II. p. 198. 

 II Magna utriufqueeft differentia, et diverfa plane ratio; 

 ideoque deoque ambo non pro uno eodemque habenda . . . fed 



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