WALTER T. ROCKEL:
In response to MOTHER's query about soap tree bark ("How to Clean Without Aerosols", MOTHER EARTH NEWS NO. 32, pg. 44); Soap substitutes are produced by several trees and plants. The best known — and probably the most widely used commercially — is Ouillaja saponaria or soapbark, a middle-sized rosaceous tree bearing undivided evergreen leaves and small white flowers, native to the Andes. The inner bark, which has cleansing and lathering properties, is often included in hair tonics and is particularly valued as a shampoo. It's also used in fire-extinguishing solutions and as an emulsifying agent for medicines and tars.
The soapberry (Sapindus saponaria), a tropical and subtropical tree, produces a lather or soap from its acrid fruits. If the berries are pounded and thrown into a body of water, any fish therein become so intoxicated that they can be caught with the hands.
Another soap producer — Sapinda mukorossi — has been used since ancient times in east Asia and the Himalayas as a detergent for shawls and silks, and by jewelers to clean silver.
The soapwort or bouncing Bet ( Suponaria officinalis, a member of the pink family) produces lather from all its parts and is the best-known soap plant in the United States. The California soap plant or soaproot (Chloragalumpomeridianum) is collected in the western part of the country for its lily-like saponaceous bulb. Other American specialties include Acacia concinna — the pods of which are used like the fruits of the soapberry — and some species of yucca and agave . . . also the red buckeye (Aesculus pavia), the California pigweed (Chenopodium californicum), the senega "snakeroot" (Polygala senega), and others.
Soap plants contain no alkali and are considered mild and beneficial cleansers (with the exception of the soapberry, which is thought to harm some textiles). The lather-producing agent in such plants is saponin, which was first observed in the common soapwort. Although many saponaceous species exist, only a few — especially horse chestnuts, senega root, and the bark of the soapbark tree — yield the substance in appreciable quantities.
To obtain saponin, the raw material is powdered, boiled in strong alcohol, and filtered while hot. The lathering agent separates in flocs as the solution cools, and is purified by means of animal charcoal. The pure form is a white, friable powder, with a burning and persistently disagreeable taste.
Saponin is often toxic when taken internally (this property made it useful to the Indians as a fish poison). The substance is more soluble in dilute than in strong alcohol, forms a frothy solution with water, and is frequently used to give an artificial froth to beer and other effervescent beverage.
Just happened to come across "soapbark" in The New Garden Encyclopedia, edited by E.L.D. Seymour, B.S.A., Wm. H. Wise & Co., Now York, 1936. Here's the information I found:
"Common name for Ouillaja saponaria, an evergreen member of the Rose Family, with small, shining, leathery leaves, and white flowers 3/4 in. across in terminal clusters. Its bark has saponaceous and medicinal qualities. Not hardy N., it is sometimes grown as a greenhouse tree in the S. States and Calif. It is increased by cuttings rooted under glass.''
I also noticed the following entry: "Soap-Plant. Common name for Chlorogalum Pomeridianum, also called Amole, a tall bulbous herb of the Lily Family, with basal leaves to 1-1/2 ft. and small white flowers with purple veins, opening only in the afternoon. The bulb is used by the Indians and Mexicans for soap-making. Easily grown, it thrives in any good (but not too rich) garden soil. Plant the bulbs in fall 3 or 4 inches deep, preferably in groups of 5 or 7. Plants may also be increased by seed. "
WOLCOTT M. SMITH:
The following is a listing from Potter's Cyclopaedia of Botanical Drugs and Preparations:
Ouillaia Saponaria, Molina
SYN.; Quillaia, Soap Bark, Panama Bark
PART USED: Bark
ACTION: Expectorant, diuretic, detergent. Used to loosen cough in chronic bronchitis and pulmonary complaints . . . A heading for beers is made from it.
PREPARATIONS: Ext. Quill. Liq. B.P. Tinct. Quill. BPC. Powdered Bark.
DISTINCTIVE CHARACTER: Imported in large flat pieces 1-2 feet long or more, 4-6 inches broad, and 1/8-1/4 inch thick. The outer surface is pale yellowish white with irregular patches of imperfectly removed reddish outer bark.
A variety of another species, less active, has brown patches over most of the outer bark. Under a lens, the better grade shows calcium oxalate crystals.
(Note: The current edition of the work quoted above is Potter's New Cyclopaedia of Medicinal Herbs and Preparations by R.C. Wren, Wehman Brothers, Hackensack, New Jersey, 1972, paperback $3.95. MOTHER.)
Jeanne Rose's fine book, Herbs and Things (available from MOTHER'S Bookshelf for $2.95) lists "soap bark" (also called "soap tree", so I figure "soap tree bark" covers it all) as a native tree of Chile and Peru. Apparently, the bark contains saponin, which forms a lather in water and is used for cleansing. It's also used as a diuretic, a detergent for skin ulcers and eruptions, an expectorant for chronic bronchitis, and as a local anesthetic. The substance reduces favor, and is good as a wash for eruptions, scalp sores, and — as Ms. Rose so diplomatically puts it — "funky feet". And the brewing industry mixes the bark into their concoctions to produce a foamy head on beer. So there you have it!
(Thanks to all the readers who responded to my query in MOTHER EARTH NEWS NO. 32. If you'd like to test the cleansing properties of Quillaja saponaria the powdered bark is available in 50c or $1.00 boxes — weights not given — from Indiana Botanic Gardens, Inc., Hammond, Indiana. Bulk prices for quantities of two pounds or more are available on request. Or, if you'd prefer to grow your own soapbark tree, you can obtain seedlings for $2.00 each from Logee's Greenhouse, Danielson, Connecticut. Minimum order from this firm is $6.00, and handling and shipping charges are extra Fanciers of begonias, geraniums, herbs, and rare plants will enjoy Logee's catalog. — MOTHER.)