Abstract
Summary
1. A total number of 87 assays of estrin were done on female stock urine. Fifteen were done after acidification of the urine with sulphuric acid, 17 with hydrochloric acid, 24 with glacial acetic acid, 18 with trichloracetic acid, and 13 with tartaric acid. 2. It has been shown that, by the use of the described method, varying yields of estrin are secured by extraction and assay of urine which has been acidified with various acids. 3. Extractions made after acidification with sulphuric and hydrochloric acids gave negative results. 4. Extracts made after the acidification with glacial acetic, trichloracetic, and tartaric acids all contained measurable amounts of estrin. 5. Of the 3 acids mentioned, urine acidified by the use of tartaric acid produced the greatest yield of estrin as assayed by the method described in this paper.
The author whishes to express his appreciation to Miss Bernice Morrison for her valuable technical assistance.
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