[Letter to Editors]

Abstract

THREE further references to work on Dichroa febrifuga can be added to those quoted above : they are Tonkin and Work, Nature, 156, 630 (1945) ; Cheng Fang Tsu, J. Trop. Med. and Hyg., 75 (April, 1947) ; and J. B. Koepfli, J. F. Mead and J. A. Brockman, J. Amer. Chem. Soc., 69, 1837 (1947). Dr. Koepfli refers to the earlier work of Dr. Jang and directs attention to the disparity in melting point between his own and Dr. Jang‘s active alkaloid. The new results now presented by Dr. Jang do not resolve this difficulty. Dr. Koepfli suggests, however, that, at any rate in leaf, the biological activity is not accounted for by the active alkaloid which he isolated; thus several related bases may be present. It should also be noted that Dr. Koepfli suggested the active principle was a quinazoline derivative, a conclusion which is now reached by Dr. Jang also.