Manna
2 of the 6 encyclopedias on this shelf carry an entry for Manna. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
"a small, round thing, as small as the hoar frost," which lay on the face of the wilderness every morning except on the Sabbath (Exod. xvi: 14, 26, 27), sent by Jehovah as bread rained from heaven (ver. 4, 5), and continued during the whole 40 years of the Israelite wanderings in the wilderness (ver. 35). It melted when the sun became hot (ver. 21), and if left till next day bred worms and stank (ver. 20). An omer of it was preserved to show to future generations the nature of the food divinely provided in the desert. Attempts have been made to identify it with some of the other substances now named manna. In botany, a concrete discharge from the bark of Fraxinus rotundifolia and some other species of the genus, including in the S. of Europe the common ash, F. excelsior. The sweetness is due to the presence, not of sugar, but of mannite. Eucalyptus mannifera, an Australian tree, exudes a substance like manna, but less nauseous. Manna of Briançon is an exudation from the common larch. Manna of Mount Sinai is an exudation produced by the puncture of an insect, Coccus manniparus on Tamarix mannifera. In chemistry, a saccharine juice which 1 exudes from certain species of ash, chiefly Fraxinus ornus, found growing in the S. of Europe and in Asia Minor. It has an odor resembling that of honey, and tastes nauseously sweet, with a slight acridity. It is soluble in water and alcohol, and its aqueous solution readily undergoes fermentation, yielding a liquid a peculiar odor and with containing butyric acid.
Aiton's Encyclopedia (1910)
in the drug trade, a white, sweetish, flaky gum collected from the stems of a sort of ash grown chiefly in Sicily. The Sicilians raise plantations of young ash for the purpose. The manna is obtained by making short incisions in the bark. The manna exudes and dries, after which it is removed with wooden knives and is dried in the sun for shipment. In medicine it is used as a laxative, especially for children. The manna of the Israelites is supposed to be a somewhat similar substance exuded in June and July from the stems of the tamarisk, a shrub growing abundantly in the peninsula of Sinai. It has the form of drops of honey, which, in the cool temperature of the early morning, may be gathered in a solid state. It is gathered in small quantities by the Arabs and sold to pilgrims.
What Has Changed in the Last Century
Aiton's 1910 description of Sicilian ash plantations tapped with incisions and scraped with wooden knives is still accurate in outline, but the industry has all but vanished: manna from Fraxinus ornus now survives as an artisan product of a few villages in the Madonie mountains of Sicily, chiefly Castelbuono and Pollina, rather than a staple of the drug trade, and its use as a children's laxative has been displaced by modern preparations. The "mannite" Collier's noted in 1921 has had the larger career: mannitol is made industrially from sugars and is a standard hospital drug, given intravenously as an osmotic agent to reduce raised pressure inside the skull, as well as a bulk sweetener. On the biblical question both entries hedge; the tamarisk suggestion Aiton's reports was argued in detail by the entomologist F. S. Bodenheimer in the 1940s, who identified the substance as honeydew excreted by scale insects feeding on Tamarix, and this remains the most commonly cited natural explanation, alongside proposals involving desert lichens. None of these accounts for the narrative details the 1921 entry lists, such as the Sabbath pause, and scholars now generally treat the Exodus account as a theological narrative rather than a record to be matched to a plant product.
Written for this edition, 2026.