This section is from the book "A Dictionary Of Modern Gardening", by George William Johnson, David Landreth. Also available from Amazon: The Winter Harvest Handbook: Year Round Vegetable Production Using Deep Organic Techniques and Unheated Greenhouses.
Several plants are popularly known under this name. "The Balm of Gilead of commerce is the dried juice of a low tree or shrub [amyris gileadensis), which grows in several parts of Abyssinia and Syria. This tree has spreading, crooked branches; small, bright-green leaves, growing in threes; and small, white flowers on separate footstalks. The petals are four in number, and the fruit is a small, egg-shaped berry, containing a smooth nut. By the inhabitants of Syria and Egypt, this balsam, as appears from the Scriptures, was in great esteem from the highest periods of antiquity. We are informed by Josephus, the Jewish historian, that the balsam of Gilead was one of the trees which was given by the queen of Sheba to king Solomon. The Ishmael-itish merchants, who were the purchasers of Joseph, are said to have been traveling from Gilead, on the eastern side of Canaan, to Egypt, and to have had their camels laden with 'spicery, balm and myrrh.' It was then, and is still, considered one of the most valuable medicines that the inhabitants of those countries possess. The virtues, however, which have been ascribed to it exceed all rational bounds of credibility.
The mode in which it is obtained is described by Mr. Bruce. The bark of the tree is cut with an axe, at a time when its juices are in their strongest circulation. These, as they ooze through the wound, are received into small earthen bottles; and every day's produce is gathered, and poured into a larger bottle, which is closely corked. When the juice first issues from the wound, it is of a light-yellow colour, and a somewhat turbid appearance; but, as it settles, it becomes clear, has the colour of honey, and appears more fixed and heavy than at first. Its smell, when fresh, is exquisitely fragrant, strongly pungent, not much unlike that of volatile salts; but if the bottle be left uncorked, it soon loses this quality. Its taste is bitter, acrid, aromatic and astringent. The quantity of balsam yielded by one tree never exceeds 60 drops in a day. Hence its scarcity is such, that the genuine balsam is seldom exported as an article of commerce. Even at Constantinople, the centre of trade of those countries, it cannot, without great difficulty, be procured. In Turkey, it is in high esteem as a medicine, an odoriferous unguent and a cosmetic.
But its stimulating properties upon the skin are such, that the face of a person unaccustomed to use it becomes red and swollen after its application, and continues so for some days. The Turks also take it in small qantities, in water, to fortify the stomach." - Encyc. Am.
 
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