Section 19: It shall be lawful for the Governor in Council to add to

Schedule B, with or without modifications, the names of any substances and articles which are to be treated as poisons by virtue of any Poisons List Confirmation Order made under section 17 (4) of the Imperial Pharmacy and Poisons Act, 1933, (23 and 24 Geo. 5, cap. 25), and to Schedule F, any simple medical substances approved as such by the Director of Medical Services: Provided that any additions to Schedule B shall, when made, be published in the Gazette, and shall not have effect until the expiration of one month after such publication.