LSD. REACTIU4 BY PRETREATlv'ENT ATTEIVIPTS TO BLOCK I'Hr wlrh BOL FOR l@y@--DAYS These experiments were carried out because of the -Gross that 2 day's pre- reports of Ginzel and Mayer letely blocked the LSD re2action treatment with BOL comp and one-day's pretreatment wlfh BOL attenuated It. accause of shortage of BOLs only 8 subjects could had not had LSD before be used. Six of these subjects Insofar- as was possible$ we attempted to reproduce the expe"riment of Ginzel and &layer-Gross,, The drug combl- nations use2d were: BOL placebo and LSD placebo; SOL and lus LSD. Combination SOL plus LSD; and SOL. placebo p LSD placebo was not studied because of the shortage of material and because it was believed that the results tially similar to those described under would be essen ration of SOL. acute administ 2 ily, I mg* was given three times BOL was given ora datl.y for two days prior to administration of LSD, and an additional I mg. was given two hours prior to LSD. mcgm./k.g.. of bodyweighf* Dose of' LSD 'varied between kleasurements included threshold for kneeierk, pupillary size.,5-resting systolic blood pressures, responses E F F 'S UF I @4 I S TE R lt,.G 3C kiG. UF SOL D,,AILY FOR 2 DAYS BEFORE LSD i',EASURE DRL)G BUL 4, 2BOL PLACESU BUL PLACEC@)C) LSD 4- LSD LSD PLACEEL) 0. 06 0. 1 @4 )atellar Reflex 1.07 4 0.223 1.91 4. 0.3 3. 88 4 0.76 5pup a r y 3 I.ze 3.19 0.45 0.15 4. m.29 Systolic Blood Pressure 1.90 4. C.34 2.76 0.27 '@1.41 4. 0.26 ,4umb,z r of @:.)uz s tons 13 4. 7.5- S7 35 1.3 1.@^7 :Iinical Grade O.'J'7 4. C.IS 0.9 4 0.48 0 0 1.0 mg. of BUL was 2 given three times daily for,'4 ddYS prior to LSD and an additional dose given 2 hours prior to LS,:). Dosage of LSD varied from 1.0-2.0 mcg./kg. teve.1.4 mcg./kgl. Figures are means standard crrers on 8 subjects.