26 On ihe Efftcts of Opium 



PART THE. SECOND, 



fit l^Ai 



ittM P i^l^,:tW^U^'<kotii^c operation of opiiipi f' 



Ever, .sincp..., the introduction of. this most 

 powerfuV^nd e-^cacipus ^rtkle intq the ^jist of 

 ^ the Materia- ^iedica,- 3tnuch, diversity of opinion 

 has arisen aqiofigst medical'men, respecting the 

 qualities it po^ssesses. It .would be foreign to 

 Ojur.jpuvpose to enter into a discussion respecting 

 thq ; various, theories A^v^high at different times 

 h^,ve prevailed upon this subject, as experience 

 and a clearer insight ,into the nature of the 

 animal machine, have exploded all other opi- 

 nions except two (opposite indeed to each 

 other), namely, the x)ne which explains the 

 operation of this power by attributing a stimu- 



excite a muscle (o contract, because a certain portion of 

 irritability is present, as it appears to bestow irritability, 

 if this principle is not too much extinguished and the 

 viialiry gone, A muscle which is incapable of contracting 

 on the application of a mechanical stimulus, and is re- 

 laxed and pale, will, on the application of salt, exhibit very 

 frequent and strong contractions, assume graciually a 

 beautiful florid colour, and will then become obedient 16 

 Giber stimuli, to which before.it was insensible. Thus it 

 will be found to be a belter restorer of irritability to the 

 muscular fibre, than muriatic acid, related by Humbolt. 



