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(6)③)

I was away from Lexlncton last week so the preliminery descrlptlon of the C- could not be completed until my return. This has now been finished and is attached to the original letter.

Since wrifing you on May 23rd fhe work with Frenquel orally as a blocker of LSD has been completed and table giving the results is attached. You will note that the differences between placebo-LSD and Frenguel-LSD are insignificant. It Is concluded that in:the dosage used Frenquel is Ineffective in altering the LSD-reaction. t am, of course, sending these data on to the Wm. S. iverrell'Company, who so kindly supplied me with the- drug. I am also thinking of sending a short note to Sclence concerning thesz negative results.

Trials of synthetic LSD are underway. Mild but definite LSD-like cffects have been observed with this material in doses of 25 mcgm. Trlals of larger doses should begin next week.

Very sincerely yours,

Narri Sbel

Harris Isbell. M.D. Directcr of Research

ment of HEALTH. EDUCATION. AWEL RE· Publie Health Service NATIONAL INSTITUTES OF HEALTH 1 June 1955

1N.REPLYINE. AODR求S\$ THE ADDICTION RESEARCH CENTEP NATIONALÍNTITUTES OF MENTAL HZALTH U. S. PC MALT SEV HOSITAL 30x 2000 LESINOTOR, KENTUCNY

Hl:rn

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EFFECTS OF "FRENQUEL," 2O MGM. T.I.D. ORALLY ON REACTION INDUCED BY 6O MCG. OF LSD