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I have tested the new lot of material on 3 men using doses of I to 1.5 nfg./kg. of body welght. Typical reaetions appeared which were of the same Intenslty observed in the same patients during a preceding week, using a lot of older materlal. l, therefore, fel that the new materlal is biologically actlve as the old, and that any further testing of it Is unnecessary. lf you wtsh more extensive -testing please let me know.

fncems onSo Sopie二次

i am enclosing a table showing results obtained when 2-4 mg./70 kg. of, BOL-l48 were administered simultaneous ly with .5-l.5 mcg./kg. of LSD. There is, obviously, no statistical dtfference In any of the measurements.

I have. obtained a copy of Nature contalnlng the paper by Ginzel and Mayer-Gross. in which blocking of LSD-25 by BUl was reported. Thls apparently occurred only when BCl was given for at least two days prlor to LSD. I will proceed to investigate this. It sounds more like tolerance than it does like competitive blocking. Others also report that Intravenous injectlon of Bul at the helght of the reaction did not alter the LSOreactlon.

Very sincerely yours,

Harris lsbell, M. D. Director

Deod of HEALTH, EDUCATION, AND , \_LrARPulHealth Service NATIONAL INSTITUTES OF HEALTH

IM AEPLTPNG ADDE\$1 THENAIONAL UT O NTAL HELTAORIETON RESEAACH CENTENU.S, POMLIC HEALTH SELRYICE HOSPTTALP. 、  200LEXNTON, KENTCE

8 March 1957

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