<< There's a mention "astoreum: reddish glands found in the groin of the beaver
and widely used in medieval medicine..." >>
Johnnae, did you mean "Castoreum"?
Rumpolt has this beaver recipe (Von einem Biber):
http://diglib.hab.de/drucke/2-3-oec-2f/start.htm?image=00220
E.