The Drugs Act, 1940, as it was substituted by the Drugs (Amend ment) Act, 1955 (16.4.55) had defined "drug" in Section 2(b) to include "(i) all medicines for internal or external use of human beings or animals and all substances intended to be used for or in the diagnosis, treatment, mitigation or prevention of disease in human beings or animals other than medicines and substances exclusively used or prepared for use in accordance with the Ayurvedic or Unani systems of medicine; and (ii) such substances (other than food) intend ed to affect the structure or any function of the human body or intended to be used for the destruction of vermins or insects which cause disease in human beings or animals, as may be specified from time to time by the Central Government by notification in the Official Gazette." (Emphasis supplied) Section 3(i) of the Act provides that "there shall be levied duties of excise, at the rates specified in the Schedule, on all dutiable goods manufactured in India.