Medicine Duty ...

 I was down in Chiltern earlier this week and came across ( and solved) this little puzzle

A Medicine Duty tax stamp was a long stamp as in this 1897 example:

and would have been attached in such a way as to seal the package, or over the cork in the case of a bottle, meaning that when the item was opened the stamp would have been ripped off, making bottles with stamps in place pretty rare, as in this screen grab from a Bonham's stamp auction:

I'm not going to claim to be a genius in working this out, there was nothing particularly special in the solving of it, I found the answer via Wikipedia, with a little bit of supplemental googling about revenue stamps, but what I find quite remarkable is the way that something like this, which once must have seemed normal, too normal to mention even, can disappear from the collective memory ...