Dictionary of National Biography, 1885-1900/Hennen, John
HENNEN, JOHN, M.D. (1779–1828), army surgeon, born on 21 April 1779, at Castlebar, co. Mayo, was the younger son of James Hennen, and descended from a family who had held land near Castlebar since the Cromwellian occupation. From school at Limerick he became medical apprentice to a near relative (his father?) at Castlebar. In 1796 he entered the medical classes at Edinburgh, was more gay than studious, and married, when under eighteen, Miss Malcolm of Dumfries. He qualified at the Edinburgh College of Surgeons in 1798, joined the Shropshire militia as assistant-surgeon, in 1800 was appointed to the 40th regiment, and went with it to the Mediterranean. He served through the Peninsular war in various regiments, and became staff-surgeon in 1812. He became known as a skilful operator and energetic officer, and was also noted for being never without a cigar in his mouth. He retired on half-pay in 1814, but had hardly settled at Dumfries when he was recalled to active service in Flanders. For his services after Waterloo he was promoted to the rank of deputy-inspector of hospitals, and placed on the home staff at Portsmouth. There he utilised his abundant notes of cases to write his ‘Observations on some important points in the Practice of Military Surgery; and in the Arrangement and Police of Hospitals,’ which he finished and published in 1818 at Edinburgh, whither he was transferred in 1817 as principal medical officer for Scotland. A second edition was published in 1820 with the title ‘Principles of Military Surgery,’ and a third edition with life by his son in 1829. At Edinburgh he attended the classes a second time, and graduated M.D. in 1819. In 1820 he was appointed principal medical officer in the Mediterranean, residing at Malta and Corfu. His ‘Medical Topography’ of these islands and of Gibraltar, in the form of reports to the army medical department, was brought out by his son in 1830. In 1826 he became principal medical officer at Gibraltar, and died there on 3 Nov. 1828 of a fever (yellow fever?) which he contracted in combating the disastrous epidemic which had broken out in the garrison in September of that year. A monument to him was erected by subscription at Gibraltar. He was twice married and left five children.
[Biography by D. O. Edwards in Lancet, 1828–9, ii. 44; Edinb. Med. and Surg. Journ. xxxi. 225, 1829; Life by his son, prefixed to 3rd edition of Military Surgery.]