19. Every Inspector or medical practitioner, who gives to any parent or guardian a certificate in any of the forms of the said Schedules A, B and C, shall, within twenty-one days after giving the same, transmit a duplicate thereof to the Registrar of Births of the district where the birth of the child on whose account such certificate was given has been registered; or, if that be not known to him, to the Registrar of the district within which the child was vaccinated or presented for vaccination.