Canada Balsam
a pale balsam, resin, or oleoresin, obtained by incision from a Canadian tree, the American silver-fir, sometimes called the Balm of Gilead fir (Abies balsamea). Canada balsam is of the consistence of thin honey, drying slowly by exposure to the air into a transparent adhesive varnish.
It is used to mount objects for the microscope and for other optical purposes.