𝔖 Bobbio Scriptorium
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The thirty-meter laser interference comparator which forms part of the state primary standard of the unit of length – the meter

✍ Scribed by Yu. G. Zakharenko, N. A. Kononova, G. I. Leibengardt, K. V. Chekirda

Book ID
118806111
Publisher
Springer US
Year
2012
Tongue
English
Weight
241 KB
Volume
55
Category
Article
ISSN
0543-1972

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Acute and Chronic Toxicity of Veratrum V
Acute and Chronic Toxicity of Veratrum Viride††The Veratrum viride studied was the whole-powdered drug marketed by Irwin, Neisler & Co. under the name, Vertavis. The work reported herein was supported by a grant from this firm. The batch of powder used in these experiments was stated by the manufacturer to have been assayed biologically by the Craw method on Daphnia magna. One Craw unit of the material studied was stated to be 15.6mg. With regard to this assay, Mr. R. O. Craw has been so kind as to allow us to publish a brief explanation: A reference lot of Yerolrum oirid; powder was set-aside as a standard and a 10% w/v aqueous extract was made of this powder. The average median length of life in 50 assays of 1000 daphnia on immersion in the solution was determined to be 2.22 hours. The daphnia were considered dead when the heart was found to be in systolic standstill on microscopic examination. Succeeding lots of powder were assayed and their potency determined by relating the median length of life of daphnia to 2.22 hours, which is one unit. Twenty assays of 10 animals each were used on each lot of powder.‡‡The authors wish to thank Dr. J. F. A.,McManus of the Department of Pathology for a pathologic report on the tissues, and Mr. James Thomas and Mrs. Bobby E. Teague for technical assistance.
✍ Perdue, Adoline S. ;Bell, Frances ;Starnes, W.R. ;Hitchcock, Philip ;Teague, R.S 📂 Article 📅 1950 🏛 Elsevier ⚖ 346 KB 👁 2 views