Propolis while also collecting water and tree resin necessary for the production of propolis. The chemical composition and nature of propolis depend on environmental conditions and harvested resources. For centuries, beekeepers assumed that bees sealed the beehive with propolis to protect the colony from the elements, such as rain and cold winter drafts. However, 20th century research revealed that bees not only survive, but also thrive, with increased ventilation during the winter months throughout most temperate regions of the world. Propolis properties may include: The composition of propolis varies from hive to hive, from district to district, and from season to
Rabbit-skin glue glue does. However, these modern replacements do not stiffen and tighten the canvas as well as rabbit skin glue does, so some artists still prefer to use rabbit skin glue. Rabbit-skin glue Rabbit-skin glue is a sizing that also acts as an adhesive. It is essentially refined rabbit collagen, and was originally used as an ingredient in traditional gesso. In traditional oil painting as practiced by the Renaissance painter, skin glue was used to coat the canvas. This is necessary because the linseed oil that forms the base of most oil paint contains linolenic acid that will destroy the canvas