10 On the Ejects of Option 



truth of it. I followed the method described 

 by Fontana, and I found the fact to be cot- 

 rectly as he relates it ; the divided extremity 

 of the crural nerves, bared for the space of half 

 an inch arid im'mersed in solutions of opium of 

 various degrees of strength, was ri'ot more af- 

 fected than If the same nerves had been im- 

 mersed in water, and the irritability of thfe 

 muscles, to which they wxre distributed, was 

 not in the l^ast degree more altered. 



Althougli I admit the accuracy of thfese ex- 

 periments, I am inclined to call in question the 

 sufficiency of them for the purpose they w^ere 

 designed. There is a considerable difference 

 betwixt the sentient and the divided extremity 

 of a nerve. This operation, even if the struc- 

 ture of the divided part was capable of receiving 

 and communicating impressions, must in a 

 great measure have had the effect of destroying 

 its sensibility, and though the solution was not 

 only applied to the divided extremity, but iilso 

 enveloped the surface of the nerve for a con- 

 siderable distance, this surface must also have 

 lost in consequence of being separated fi'om the 

 muscles by *' scissars and pincers" so much of 

 the usual quantum of sensibility as to be un- 

 equal to transmit any effect produced upon it. 



Respecting the second series of experiments, 

 they are so contrary to all that repeated ex- 



