This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
This is prepared from the roots of Veratrum album and V. viride, and is a popular remedy against attacks of leaf-eating insects and caterpillars. The powder is a poisonous alkaloid, but loses its property by keeping. Fresh powder, therefore, should be used, and may be distributed by means of a perforated tin or through a piece of muslin. If used as a solution (which is the most economical method), 2 1/2 lb. fresh Hellebore powder should be added to 10 gal. water, and well stirred while spraying.
This has already been referred to as a vaporizer and fumigant at p. 169.