A fair yield per acre of seeds is about 1,000 pounds. The plant yields on distillation 0.3 to 0.6 per cent of volatile oil, the fruits being the parts richest in oil. Wormseed oil is pale or yellowish and has a penetrating, disagreeable odor. It has the property of killing intestinal parasites.
Literature.
General : Wm. Dymock, C. J. H. Warden and David Hooper, Pharmacographia Indica. A History of the Principal Drugs of Vegetable Origin met with in British In lia, three vols, Began Paul, Trench, Tribner & Co., London., 1590-1S93; H. W. Feller and J. U. Lloyd, King's American Dispensatory, third edition, two vols., The Ohio Valley Company, Cincinnati, Ohio, 1898 (numerous illustrations); F. A. Fliickiger and Daniel Hanbury, Pharmaco graphia, A History of the Principal Drugs of Vege table Origin, second edition, Macmillan & Co., London, 1879; H. A. Hare, Charles Caspari, Jr., and H. H. Busby, The National Standard Dispen satory, Containing the Natural History, Chemistry, Pharmacy, Actions and Uses of Medicines, Lea Bros. & Co., Philadelphia and New York, 1905 (numerous illustrations) ; Laurence Johnson, A Manual of the Medical Botany of North America, William Wood & Co., New York (illustrated); J. U. Lloyd and C. G. Lloyd, Drugs and Medicines of North America, Vol. I and part of Vol. II, Cin cinnati, Ohio, 1884-1887 (illustrated); Charles F. Millspaugh, American Medicinal Plants: An Illus trative and Descriptive Guide to the American Plants Used as Homeopathic Remedies, two vols.,
1887 (many colored plates); Francis Peyre Porcher, Resources of the Southern Fields and Forests, Medical, Economical and Agricultural, Being also a Medical Botany of the Southern States, Walker, Evans & Cogswell, Charleston, S. C., Revised edition, 1867; H. C. Wood, J. P. Remington and I. P. Sadtler, The Dispensatory of the United States of America, J. B. Lippincott, Philadelphia, 1907 (numerous illustrations). Bulletins of the United States Department of Agriculture : Alice Henkel, Weeds Used in Medicine, Farmers' Bulletin No. 188 (1904); Peppermint, Bulletin No. 90, Part III (1905); Wild Medicinal Plants of the United States, Bulletin No. 89 (1906); Alice Henkel and G. F. Klugh, Golden Seal, Bulletin No. 51, Part VI (1905); W. W. Stockberger, The Drug Known as Pinkroot, Bulletin No. 100, Part V (1906); Rodney H. True, Cultivation of Drug Plants in the United States, Yearbook of the United States Department of Agriculture, 1903; Progress in Drug Plant Culti vation, Yearbook of the United States Department of Agriculture, 1905. Special articles on various drug plants may be found in the files of the Pro ceedings of the American Pharmaceutical Associa tion, and the various pharmaceutical periodical publications. The agricultural aspect of the cul ture of ginseng, golden seal, and others, is espe cially noticed in a monthly publication called "Special Crops," edited by C. M. Goodspeed, Skaneateles, N. Y.