I found this article absolutely revealing.
I hope youŽll find it interesting too.
http://www.druglibrary.org/shaffer/MISC/ciaopium/htm
About this site:
DonŽt forget to click on the link "Library table of contents"; this siteŽs content can only be compared with erowid for completeness and authorithy as source for drug related information. Here I found extremely interesting papers on all drug related subjects: legal, sociological, medical , administrative, historic, literary, etc. etc.
IŽm sure many members already knew of this library but those who didŽnt i think will be grateful for this adress.
VV.