HIGH PURITY (1R, 2S, 4R)-(-)-2-[(2'-(N,N-DIMETHYLAMINO)-ETHOXY)]-2-[PHENYL]-1,7,7-TRI-[METHYL]-BICYCLO[2.2.1]HEPTANE AND PHARMACEUTICALLY ACCEPTABLE ACID ADDITION SALTS THEREOF, PROCESS FOR THE PREPARATION OF THESE COMPOUNDS AND MEDICAMENTS CONTAINING THEM.