James Douglass was treating patients at the Manning River by 1849 
In October 1852 he took over the Maitland practice of Mr. John Scott who had temporarily relinquished the business due to ill health and moved to Newcastle. The surgery was probably situated in High Street, West Maitland in Thomas Dee's Cottage formerly occupied by Mr. Chambers, solicitor (near Rev. Purves's Church).
James Douglass died in 1897 - Douglas, April 27, at his late residence 80 Glebe Road, (Sydney) James Douglas surgeon, only son and last surviving child of the late Major James Douglass, of the East India Co., Service, who died at Edenside, Kelso, Scotland in his 94th year. 
His obituary was published in the Maitland Weekly Mercury -
The death is recorded of Mr. James Douglass, surgeon at the age of 93. He was born in Bombay on 25th February 1804. He was the only son of Major James Douglas EI. Company's service, was educated at the High School, Edinburgh and studied medicine at the University in that city. He afterwards served as a surgeon under Sir C. Napier. In 1839 he came to this colony, settled at Stroud, and then on the Manning. In 1853 he removed to Maitland where during a residence of 11 years he gained general esteem. Owing to threatened paralysis he in 1864 removed to the Glebe, where he continued the practice of his profession for some years. For the past few years he has been confined to his house through weakness, but was free from pain and retained his faculties and cheerfulness to the last. He was a man of broad sympathies and took a hearty interest in all efforts to help his fellows. By his death the New South Wales Auxiliary to the British and Foreign Bible Society loses one of its oldest supporters and vice presidents. He was buried at Balmain Cemetery the Rev. T.E. Clouston B.A. conducting the service. The Rev. R.T. Hills also took a part in it and many old friends o the deceased were also present.