He was educated at private schools, and became a fellow of the Royal College of Surgeons in 1844. For several years he followed his profession of surgeon, but gradually abandoned it on account of the success of his works on the subject of sport. He removed from the country to London in 1852, and the following year brought out his first important book, The Greyhound (3rd ed. 1875), a collection of papers originally contributed to "Bell's Life."
In 1856 his Manual of British Rural Sports appeared, which enjoyed many editions. During the same year he joined the staff of The Field, and became its editor at the close of 1857. Among his numerous books published under the name of "Stonehenge" are:
While editor of The Field Walsh instituted a series of trials of guns, rifles and sporting powders extending over a period of many years, which greatly tended to the development of sporting firearms; and his influence upon all branches of sport was stimulating and beneficial.
Walsh, son of Benjamin Walsh, was born at Hackney, London, on 21 Oct. 1810, and educated at a private school. In 1832 he passed as a member of the Royal College of Surgeons, and became a fellow of the college by examination in 1844. For some time he was surgeon to the Ophthalmic Institution, and lectured on surgery and descriptive anatomy at the Aldersgate school of medicine. For several years he was in practice at Worcester, but left that city for London in 1852. He always had an intense love of sport, he rode well to hounds, kept greyhounds and entered them at coursing meetings, broke his own pointers and setters, and, what is far less common, also trained hawks. In the management of dogs he became an especial adept, and few veterinary practitioners could compare with him in the treatment of dogs' diseases. He was also fond of shooting, and, owing to the bursting of his gun, lost a portion of his left hand.
In 1853, under the pseudonym of ‘Stonehenge,’ he brought out his work on ‘The Greyhound, on the Art of Breeding, Rearing, and Training Greyhounds for public Running, their Diseases and Treatment’ (3rd ed. 1875). This treatise was based on articles he had written in ‘Bell's Life,’ and, it remains the standard text-book on the subject. Three years later, in 1856, appeared ‘Manual of British Rural Sports,’ which treats on the whole cycle of sports, and, among other things, deals with the breeding of horses in a scientific manner. Sixteen editions of this work were published up to 1886, in the later editions articles on special subjects being furnished by other writers. In 1856 he originated the ‘Coursing Calendar,’ and conducted it through fifty half-yearly volumes. About 1856 he became connected with the ‘Field,’ and at the end of 1857 accepted the editorship. He brought out ‘The Shot-Gun and Sporting Rifle, and the Dogs, Ponies, Ferrets, &c., used with them in Shooting and Trapping,’ in 1859; ‘The Dog in Health and Disease,’ 1859 (4th ed. 1887); ‘The Horse in the Stable and in the Field,’ in 1861 (13th ed. 1890); and ‘The Dogs of the British Islands’ in 1867 (3rd ed. 1886). In the two books last mentioned he also had the assistance of other writers. In 1882–4 the ‘Modern Sportsman's Gun and Rifle’ appeared, vol. i. being devoted to shot-guns, while vol. ii. treated of rifles.
His activity in conducting the ‘Field,’ with the aid of many able coadjutors, was remarkable. He soon instituted the first ‘Field’ trial of guns and rifles, which was carried out in April 1858 in the Ashburnham grounds at Chelsea adjacent to the famous Cremorne Gardens. This trial wound up the controversy as to the merits of breech-loaders and muzzle-loaders, but before the final decisions two other trials were made, one at the old Hornsey Wood Tavern in July 1859, and the third at the Lillie Arms, Brompton, in 1866. In 1875 the value of the choke-bore system received further elucidation in another trial in the All England Croquet Club grounds at Wimbledon, of which club Walsh was an active promoter. The trial extended over six weeks, the whole proceedings being carried out under the editor's personal supervision. Again, in 1878, he endeavoured to make clear what were the respective merits of Schultze and black powder, when, besides conducting the actual competition, he himself carried out numerous experiments. One of the consequences was that light pressure with Schultze was found to produce better shooting than tight ramming, while tight wads to prevent the escape of gas and the general system known as the ‘Field’ loading also resulted. Other experiments led to his invention of the ‘Field’ force gauge, which gave results more reliable than the paper pads previously in use. In 1879 another gun trial was carried out to determine the merits of 12-bores, 16-bores, and 20-bores. In 1883 he instituted the rifle trial at Putney to demonstrate the accuracy of shooting of Express rifles at the target, and to ascertain by measurement the height of the trajectives of weapons differing in bores and in the charges used therein. Subsequently Walsh organised trials to ascertain the cause of so many breakages in guns, the testing of powders by the lead cylinder method, the various effects of nitro compounds, and the strain on the barrels of small bores. His comments on proof powder in the ‘Field,’ when he stated that the powder used in testing gun-barrels was fifty per cent. below the proof required, led to an action, the Birmingham Proof-house Guardians v. Walsh, in which, on technical grounds, a verdict was given against him of forty shillings damages (Times, 3 July, 10 Aug. 1885). As soon as the trial was over he approached the guardians with proposals for providing security for sportsmen, and ultimately succeeded in obtaining some useful changes.
Walsh was one of the founders of the National Coursing Club and of the All England Lawn Tennis Club. He had a good deal to do with the early dog shows and field trials, and was on the committee of the Kennel Club. He was a good chess player, and on the managing committees of several clubs.
He died at 43 Montserrat Road, Putney, Surrey, on 12 Feb. 1888, and was buried on 16 Feb. in Putney Vale Cemetery at Putney Common. He married, first, in August 1833, Margaret, daughter of Thomas Stevenson of Claines, Worcestershire, who died nine months later; secondly, in 1835, Susan Emily, daughter of Dr. Malden of Worcester, who died eight months later; and, thirdly, in 1852 Louisa, eldest daughter of the Rev. William Parker, who survived her husband. He left two daughters.