[PAGE 1]
(b)e)

The sample of LSD received from labeled LSD-25-5l. has now been tested. Three separate experiinents have been done.

In experiment l. four whlte subjects received in randomized order placebo, 25 mcgm of LSD-25-61; 60 mcgm LSD-25-61; 4nd 60 mcgm LSD from our old stocks. As noted in the table, average effect In these subjects appeared to be just as great wlth the new materlol at the 60-mcgn level as it was at the old.

In the second experliment, 5 experienced negro subjects recelved 60 mcgm of LSD-25-5l. ln. table 2, the results obtained are compared wlth those obtalned in a prevlous run with 60 mcgm of our standard material. It Is again obvlous that the new material is as active as the old.

In experiment 3, four of the subjects received in randomized order 60 mcgm LSD-25-ó1 and 60 mcgm old LSD. In this experlment only questionnalre and cllnical grades were used. Agala it is obylous that the new-LSD Is at least as active as the old.

In each experiment there was at least one indivldual who seemed: to obtatn more effect from the new LSD than from the old, suggesfing that the new materlal Is perhaps somewhst more potent fhan the old. The number of subjects in any of the three experiments is far too smell for thls polnt to be setfied, and to test it adequately. would require preparing fresh solufions of old and new LSD at a range of dose levels, uslng a group of at least l2 subjects. i do not belleve this would be worthwhlle uniess theze Is some reason to belleve LSD-25-ol differs chemically frcm the materlal we have been ustng.

i hope It wlll not be too long before we can have & conference about the directlon of the program here. l should be able to under toke a new series of experiments in August or September. .i will be away from Lexlngton from july 7tb the luly l3th and wlll be away from Lexington on Septcmber 9th and lOth and agsln on Noyemaber 18th and l9th. I expect to be in Chiceno in both September end November and could coatact our friends there on elther or both dates.

Sineercly yours, Herris Is5ell, M.D.

NELIISUTTS YATIONAL INSTITU OF HEALTH

I \$. OS ADDICTION RESEARCH CENTER HATIONALINNTUTES OF NENTAL HEALTH U. . PUB HALT SRYICE MOSTAL Box 2000

28 June 1955

(6)03)

hi:rn

[PAGE 2]
COMPARISON OF NEW AND OLD LSD

Experiment No.I

Averages of 4 white subjects

[PAGE 3]
Averages of 5 negro subjects.

A-194

. ExperIment No. 2

COMPARISON OF NEW AND OLD LSD

[PAGE 4]
COMPARISON OF NEW AND OLD LSD Experiment No. 3