Balsam
Balsam names 3 different subjects across the 6 encyclopedias on this shelf. Each is set out below.
Balsam a kind of resinous oil
Aiton's Encyclopedia (1910)
a kind of resinous oil. There is confusion in the use of the term. The lumberman would be surprised to learn that it is applied to anything but the fragrant, balsam-producing fir tree of his northern woods and swamps. The florist's balsam is the garden touch-me-not. The woodman of Ohio might very possibly sell you a load of resinous poplar as "balsam." Ask a druggist for balsam, and he would be likely to offer a bottle of medicine extracted from a beautiful tree of Peru and Mexico, or else balsam of Tolu from the forests of the Magdalena. Generally speaking, the term applies to a healing, medicinal, resinous oil, and to the several widely different plants producing it. The balsam of the botanist is an herb with alternate leaves, and showy, somewhat clustered, yellow flowers. There are about 220 species, most of which are natives of tropical Asia. They have been introduced into many other countries. Beside being called balsam this herb is also known as jewel-weed, or snap-weed. It grows wild in moist grounds or along brooks or streams from Nova Scotia to Oregon and Alaska, south to Florida and Missouri. The cultivated varieties are of many colors, red, white, or purple, and the flowers are larger than those of the wild species. See Balm Of Gilead
Balsam an aromatic, resinous substance
Collier's New Encyclopedia (1921)
an aromatic, resinous substance, flowing spontaneously or by incision from certain plants. A great variety of substances pass under this name. But in chemistry the term is confined to such vegetable juices as consist of resins mixed with volatile oils, and yield the volatile oil on distillation. The balsams are either liquid or more or less solid; as, for example, the Balm of Gilead, and the balsams of copaiba, Peru, and Tolu. The balsams are used in perfumery, medicine, and the arts.
Balsam the common name of succulent plants of the genus impatiens
Collier's New Encyclopedia (1921)
the common name of succulent plants of the genus impatiens, family balsaminaceæ, having beautiful irregular flowers, cultivated in gardens and greenhouses. Impatiens balsamina, a native of the East Indies, is a common cultivated species. Impatiens noli-metangere, grows wild in Great Britain, but is not native.
What Has Changed in the Last Century
The chemistry Collier's set out in 1921 -- resins mixed with volatile oils, yielding the oil on distillation -- is still how balsams are defined, and copaiba, Peru and Tolu are all still traded and still turn up in perfumery and cough preparations. Two things have moved. Balsam of Peru, which Aiton's 1910 entry describes simply as the druggist's bottle of medicine from Peru and Mexico, is now one of the standard screening allergens in dermatological patch testing, and is deliberately avoided in many products; and Canada balsam, for generations the mounting medium for microscope slides, has been largely displaced by synthetic resins that do not yellow. Aiton's count of "about 220 species" of Impatiens is now far too low -- the genus runs to something over a thousand described species -- and its most familiar garden member, the busy Lizzie, was devastated across Europe and North America by an outbreak of impatiens downy mildew beginning around 2011.
Written for this edition, 2026.