DEPARTMENT OF HEALTH, EDUCATION, AND.WELFARE PUBLIC HEALTH SERVICE 21 March 1962 Isaligool lwtitut* of M*Atal HeLitIL Aidktioe Rcieste), Cealct U.S. r,&blic He&Lth St-i- H-pita2l LezingwiL, ILientacky received-today a bottle labeled 9-Amino'-l.,2 3,4-"L-.etrahydro- acridine. On checking my stock I find ("Jhat I have 5 grams of the material which was obtained in October through Dr. Ray Shelton., Iiilliam S. Merrell & Co.,'and which is labeled tetrahydroami-noacrine.2 This presumably is the same material as that used by Samuel Gershon ("Blocking effect of tetrahydroaminoacrin-- on a new psychotorr@.1-metic.a,c@ent.," Nature 186-. 1072-1073, June 25., 1960). In that article tetrahydroaminoacr ne is designated 1,2,3,4- Tetrahydro-5-andnoacridine. The structural formula given in the article howe2ver is identical with the structural formula on the bottle I redeived from the ADolications D@-z,velopm--nt Corr,-Oany. I presume that both the comoound I received from Merrell & Co. and the one you sent me are the same, and that the difference in naming is due to some differences in the conventions for numbering the ring system. However, would you please have the che2mist check this for me? Dr. Utterback spent yesterday and today with us. I have tried to impart to him my philosodhy about clinical testing of new drugs, including the necessity for measuring things, estab- lishing the reproducibility of the measurements made, doing dose-effect curves, and making proper statistical designs. Kindest regards,, 4 Harr s Isbell,, 14.D. Director Hl:rn