The eldest son of Dr James Johnson, whose birth name was properly Johnstone, but by a clerical error at the Admiralty in his Commission as Assistant Surgeon his surname was spelled Johnson, and he appeared as such in the Navy List. There was no way to get the error corrected, and as Johnson he became one of the Physicians to William IV. Henry Johnson went to Westminster School, and then studied at St George's Hospital, where he became House Surgeon. Shortly afterwards Sir Benjamin Brodie acquired a house in Kinnerton Street, to the west of the hospital, for the teaching of anatomy and physiology. Henry James Johnson was appointed a Teacher in Anatomy and Physiology, and shortly afterwards Assistant Surgeon to St George's Hospital, where he taught in the Out-patient Department, which was then small, ill ventilated, and overcrowded. With this teaching he combined private practice at 8 Suffolk Place, Pall Mall. Between 1834 and 1837 he was joint-editor with his father of the *Medico-Chirurgical Review* and the *Journal of Practical Medicine*, to which he made many communications. He was seized with a formidable illness, the result of over-exertion, which he believed to be due to cancer of the pylorus, though others attributed his trouble to gout. He retired to Boulogne, and in the space of two years so far regained health as to return and recapture a large and lucrative practice. Meanwhile at Boulogne, during the period which followed the abdication of Louis Philippe and the *coup d'état* of Louis Napoleon, he wrote a series of letters to *The Times* under the signature of 'An Englishman', condemning Napoleon's imperial designs. His old symptoms returned, reviving his fear of cancer. He fixed his attention on a painful swelling of the tibia until Sir William Fergusson laughed him out of it by offering to amputate. He built himself a house at Ramsgate - Highview, St Lawrence - and threw himself into local politics relating to the general management and main drainage of the town, which led to prolonged litigation. Shortly before his death he received a testimonial from hundreds of the leading inhabitants. He died of old age in October, 1889.