[1] Influenced by Quaker ideas, though never admitted to the Society of Friends, Walker set up a school in Usher's Island, Dublin, in 1784, based on treating his pupils kindly.
[1] Marshall invited Walker to Naples to help introduce vaccination, and he left England in June 1800.
Returning to London in 1802, Walker on 12 August started to recommence a course of public vaccination.
On 25 August the London Vaccine Institution was formed, in which Walker was appointed to a post similar to one which he had resigned, and continued to practise in Salisbury Court.
After the establishment of the national vaccine board by the government, the Jennerian Society, at a low ebb, was amalgamated with the London Vaccine Institution in 1813, and Jenner was elected president of the new society, with Walker as director, an office which he held until his death.
[4] In 1788 Walker published in London Elements of Geography and of Natural and Civil History, which reached a third edition in 1800.
He wrote also:[1] He translated from the French the Manual of the Theophilanthropes, or Adorers of God and Friends of Man, London, 1797.