Propolis propolis has approximately 50 constituents, primarily resins and vegetable balsams (50%), waxes (30%), essential oils (10%), and pollen (5%). Propolis also contains persistent lipophilic acaricides, a natural pesticide that deters mite infestations. In neotropical regions, in addition to a large variety of trees, bees may also gather resin from flowers in the genera "Clusia" and "Dalechampia", which are the only known plant genera that produce floral resins to attract pollinators. "Clusia" resin contains polyprenylated benzophenones. In some areas of Chile and Argentina Andean valleys, propolis contains viscidone, a terpene from "Baccharis" shrubs, and in Brazil and Paraguay, naphthoquinone epoxide has
Mental substance Mental substance Mental substance is the idea held by dualists and idealists, that minds are made-up of non-physical substance. This substance is often referred to as consciousness. This is opposed to the materialists, who hold that what we normally think of as mental substance is ultimately physical matter (i.e., brains). Descartes, who was most famous for the assertion "I think therefore I am", has had a lot of influence on the mind–body problem. He describes his theory of mental substance (which he calls res cogitans distinguishing it from the "res extensa") in the "Second Meditation" (II.8) and in "Principia Philosophiae"