John Cornthwaite Bowman was appointed Assistant-Surgeon, Royal Navy, in October 1834 
He was appointed Surgeon Superintendent on the convict ship Cadet in 1849 (to VDL). He kept a medical journal on this voyage from 16th October 1848 to 17th April 1849.
John C. Bowman died in September 1851 - There was an Inquest into his death-
On Tuesday 16th September at Mylor, on the body of John Cornthwaite Bowman aged 37 years, surgeon in the Royal Navy. It appeared that on Monday, the deceased went out shooting, having with him two dogs - a large Newfoundland dog, and a kind of terrier. As some men belonging to Tregew farm were going into the house to dinner, they saw him near, and after they had entered the house, heard the report of a gun. On their going out on the farm after dinner, they found him near a hedge on the farm, lying on his back, a corpse, the two dogs lying by his side, and resisting the approach of any stranger. The gun was lying by his side, and the whole of the right side of his face was so shattered that it was impossible to recognise a feature. It would appear from the evidence of the persons who had examined the spot, that the deceased must have slipped his foot in attempting to get over the hedge, while holding the gun by the barrel in his right hand, and that in putting it down hard on the
ground to keep himself up, the concussion must have caused the gun to go off, discharging the whole contents obliquely into his head through the right jaw and cheek. The gun was loaded with small shot, some of which were afterwards extracted from the pique of his cap, which was blown off at the time of the accident. It was a double barrelled gun, and the left hand barrel, which did not go off, was found to be full cocked; so that it is probable the other barrel had also been full cocked. Verdict -accidental death.