(under subclass 91) Subject matter in which the hetero ring contains only oxygen as the hetero atom.
(1) Note. Included herein are tests for the active constituents of the cannabis drugs, i.e., derivatives of cannibinol especially tetrahydrocannabinol. Broadly claimed tests for marihuana are included herein in the absence of a clear showing that the test is for a nonhetero-O containing derivative of cannabinol, typically a hydroxyl or carboxylic acid substituted hydrocarbon.