(1) Save as hereinafter provided in this section, it shall be no defence in a prosecution under this Chapter to prove merely that the accused was ignorant of the nature, substance or quality of the drug 1 [or cosmetic] in respect of which the offence has been committed or of the circumstances of its manufacture or import, or that a purchaser, having bought only for the purpose of test or analysis, has not been prejudiced by the sale.
(2) 2 [For the purposes of section 18 a drug shall not be deemed to be misbranded or 2 [adulterated or spurious] or to be below standard quality nor shall a cosmetic be deemed to be misbranded or to be below standard quality] only by reason of the fact that—
(a) there has been added thereto some innocuous substance or ingredient because the same is required for manufacture or preparation of the drug 1 [or cosmetic] as an article of commerce in a state fit for carriage or consumption, and not to increase the bulk, weight or measure of the drug 1 [or cosmetic] or to conceal its inferior quality or other defects; or 4 [* * * * *]
(b) in the process of manufacture, preparation or conveyance some extraneous substance has unavoidably become intermixed with it: Provided that this clause shall not apply in relation to any sale or distribution of the drug 1 [or cosmetic] occurring after the vendor or distributor became aware of such intermixture.
5 [(3) A person, not being the manufacturer of a drug or cosmetic or his agent for the distribution thereof, shall not be liable for a contravention of section 18 if he proves—
(a) that he acquired the drug or cosmetic from a duly licensed manufacturer, distributor or dealer thereof;
(b) that he did not know and could not, with reasonable diligence, have ascertained that the drug or cosmetic in any way contravened the provisions of that section; and
(c) that the drug or cosmetic, while in his possession, was properly stored and remained in the same state as when he acquired it.]
6 [20.Government Analysts.— (1) The State Government may, by notification in the Official Gazette, appoint such persons as it thinks fit, having the prescribed qualifications, to be Government Analysts for such areas in the state and in respect of such drugs or 7 [classes of drugs or such cosmetics or classes of cosmetics] as may be specified in the notification.
(2) The Central Government may also, by notification in the Official Gazette, appoint such persons as it thinks fit, having the prescribed qualifications, to be Government Analysts in respect of such drugs or 7 [classes of drugs or such cosmetics or classes of cosmetics] as may be specified in the notification.
(3) Notwithstanding anything contained in sub-section (1) or sub-section (2), neither the Central Government nor a State Government shall appoint as a Government Analyst any official not serving under it without the previous consent of the Government under which he is serving.
8 [(4) No person who has any financial interest in the import, manufacture or sale of drugs or cosmetics shall be appointed to be a Government Analyst under sub-section (1) or sub-section (2) of this section.]