Depa..m   oF HEALTH/ EDUCATION, AND      ELFARE    Pu
                                                                          blic Hea-Ith Service
                                  NATIONAL INSTITUTES OF HEALTH
      PlAnO*AL INSTITUTI Of MENTAL HEALTH                 June  1957
        ACOI  ON RESIAITCR CENTER
       U.S. ftBUC MIA2I.TX SERVICS HOSPI'rAl.
            P. 0. Box zooo
           Laxisloro&
                  am enclosing topics of the     ro'.1 lowing reports which
                  think wtll Interest you:
                      1.  Comparison of ALD-52    and  LSD-25,
                     20   Comparison of'  MLD-41  and  LSD-2c!
        2             3.   Affempted Blocking of    LSD-Reacllon 5y
                          Pretreat,ment wi@,h BQL.
               As you will note,
                                    HILD Is a Psychofo.-,.rrieftc agznt -Nhfc.@,
               howzver,   is consideral-ly less pot en  f Lf han LS@20, w-Nereas
               ALD Is at   least as poient as L'JD. '@le were all-lain
               unsuccessful In o@,,taintng any significant degree of
               blocking of the LSD-reacflon by pre'reatment with SOL.
               I sm, therefore, dropping this lirte of investigation
               unless you feel that I should study some other dosace2
               schedule.
               Attempted blocking of the LSD-reac@ion wil-h dibenzylcne.,
               the adrenalyfic drug, Is now In the preliminary stage.
               A I I I ca n s a y a t f he m-ome nf I s t ha f we ha ve @ a d no
               untoward effects wher O.S.                of 'SD was given
                                               ,V   2   "    6
               f wo @@ 0 _. r sc    'T.9 ./kg . oT' d i be n ZY I I ne
                 too am sorry that    I %vill not be  go t.ng f o Europe, bu;-
               ir.y work schedule ti  so heavy that    I cannot '.spare the
                !me
                                                Ver y s Ince re I y,
                                       5         H-6rris Isbell, Me Da
                                                Director
               H I
               Enclosures