(1) Nothing in this Act or in any license granted or rule made thereunder shall extend to, or interfere with, anything done in good faith in the exercise of his profession as such by a medical or veterinary practitioner.

(2) Notwithstanding anything hereinbefore contained the 5[State Government] may 14[***] by general or special order declare that all or any of the provisions of this Act 9[except section 3] shall be-deemed not to apply to any article or class of articles of commerce specified in such order, or to any poison or class of poisons used for any purpose so specified.

(3) The authority on which any power to make rules under this Act is conferred may, by general or special order, either wholly or partially-

(a) exempt from the operation of any such rules, or

(b) exclude from the scope of the exemption provided by sub-section (1),any person or class of persons either generally or in respect of any poison specified in the order.