A letter written by the father of vaccination Dr Edward Jenner to a fellow physician who had supported his pioneering work is expected to fetch up to £8,000 at auction.
In 1798, Dr Jenner published his study of the cause and effects of the disease now known as cowpox and how it could act as a vaccine for the smallpox virus.
Four years later, he wrote to Dr John Glover Loy, a Whitby-based doctor, to thank him for his own work.
Dr Jenner wrote to Dr Loy to thank him for his research vindicating his theory about his smallpox vaccine (Dominic Winter Auctioneers/PA)