Section 13. Prohibition of registration of names of chemical elements or international non-proprietary names.

No word-- (a) which is the commonly used and accepted name of any single chemical element or any single chemical compound (as distinguished from a mixture) in respect of a chemical substance or preparation, or (b) which is declared by the World Health Organisation and notified in the prescribed manner by the Registrar from time to time, as an international non-proprietary name or which is deceptively similar to such name, shall be registered as a trade mark and any such registration shall be deemed for the purpose of section 57 to be an entry made in the register without sufficient cause or an entry wrongly remaining on the register, as the circumstances may require.