(a) morphine, cocaine, (including synthetic cocaine), ecgonine, diacetylmorphine (commonly known as diamorphine or heroin) and their respective salts, medicinal opium, and any extract or tincture of Indian hemp, and any preparation, admixture, extract or other substance containing any proportion of diacetylmorphine or of the other esters of morphine, and any preparation, admixture, extract or other substance containing any proportion of ecgonine or of the esters of ecgonine; for the purpose of the foregoing provision the expression “ecgonine” means laevo-ecgonine and includes any derivatives of ecgonine from which it may be recovered industrially, and the percentage in the case of morphine shall be calculated as in respect of anhydrous morphine;