John James Lancaster was born at Plymouth c 1804, the son of Lieutenant Robert Daniell Lancaster.
Lord William Bentinck to Bermuda in 1831
He was employed as Acting Surgeon-Superintendent on the convict ship Lord William Bentinck transporting prisoners to Bermuda in 1831. He kept a medical journal from 21st March 1831 and 12 May 1831. 
He was appointed Assistant Surgeon to the Blanche in the West Indies on 9 May 1832 
He was employed as Hospital Mate at Jamaica commencing 18 February 1833. 
Assistant Surgeon Despatch
In December 1833 John Lancaster was employed as assistant-surgeon on the Despatch when that ship captured the vessel Rosa which was sailing under a Spanish flag on a voyage from Africa to Santiago with slaves. 
He was on the Navy List of 1834 of Officers serving abroad.
In 1835 he was appointed Acting Surgeon to the Pluto and in 1841 he was appointed Surgeon to the Daphne.
Navarino to VDL in 1842
John Lancaster was employed as Surgeon-Superintendent on the convict ship Navarino to Van Diemen's Land in 1842. - Medical Journal from 16 August 1842 to 30 January 1843.
Lord Auckland to VDL in 1844
The Morning Post reported on 29 June 1844 that the Lord Auckland, John J. Lancaster, Surgeon Superintendent, was lying off the Dockyard, Woolwich with detachments of the 58th Regiment on board and was expected to receive from two hundred and forty to two hundred and fifty convicts from the Millbank Penitentiary to convey them to the penal settlement in Van Diemen's Land.- Medical Journal from from 21 June to 21 November 1844.
John James Lancaster can be found in the 1851 Census residing at 13 Sugnall Street, Liverpool with his wife Mary Ann and their two daughters Mary age 11 and Elizabeth H age 8 and sons Robert age 4 and John age 1. John James 47 years of age and Mary Ann 35. Of their children Mary and Elizabeth were born at Jersey, Robert at Edinburgh and John in Liverpool. The family employed two servants.
MRCS Jan 29th 1828; FRCS (by election) Aug 26th 1844; MD Edinburgh 1846; Surgeon RN.
John James Lancaster died at Liverpool on 8 December 1857 and was buried in the Toxteth Park Cemetery. 
 Ancestry.com. UK, Royal Navy Medical Journals, 1817-1857. Medical Journal of John James Lancaster on the voyage of the Lord Bentinck to Bermuda in 1831 The National Archives. Kew, Richmond, Surrey.