V O L U M E 26, NO. 12, D E C E M B E R 1 9 5 4 other interferences. These must be present in relatively large amounts and will not interfere with the present determination, in which only the compound (usually 0.1 to 0.5 mg.) is present. However, any attempt to analyze for compounds containing methylrnedioxyl groups in t.he presence of foreign material must take into account this source of interference. ACKNOWLEDGMENT
The author is grateful to W.F. Barthel, S. I. Gcrtler, M. S. Schechter, and Martin Jacobson, of the Entomology Research Branch, and Lyndon F. Small and J. L. Hartwell, of the National Institutes of Health, for supplying compounds used in this study. LITERATURE CITED (1) Beroza, XI., AIVAL. CHEM.,25, 177 (1953). (2) Bricker, C . E., and Johnson, H. R., IND.ENG. CHEM..AIV
