"American medicinal barks" by Alice Henkel is a scientific bulletin written in the early 20th century. It surveys the barks of North American trees and shrubs used in medicine, providing identification, collection and preparation methods, trade considerations, pharmacopoeial status, and customary uses. Intended as a practical guide and reference, it couples botanical detail with market-oriented advice and cautions about sustainable harvesting. The opening of the bulletin sets the official context (a U.S. Department of Agriculture publication), states the scope (35 drugs, covering both “official” and “nonofficial” barks), and explains its purpose as a guide rather than a prescriptive medical text. It warns that indiscriminate bark stripping harms forests and urges careful methods and replanting, then outlines best practices for harvesting (chiefly spring or late fall), rossing and peeling, drying and packing, and consulting dealers because prices fluctuate. The text then begins a series of concise species profiles that combine habitat and range, diagnostic features, the look and feel of the commercial bark, collection timing, typical market prices, and principal medicinal actions. Early entries span a wide range—from white pine, tamarack, aspen, and willow to sassafras, witch-hazel, wild cherry, prickly ash, wahoo, horse-chestnut, and cascara sagrada—with cotton introduced next. (This is an automatically generated summary.)