Despite the fact that the TV show version of him let many fans down, Toby is a rather important character in the Conan Doyle’s universe.
Half spaniel and half lurcher, Toby is Sherlock Holmes’s other persnal assistant (no offense, Dr. Watson) on occasion to follow scent trails.
Firstly appearing in The Sign of the Four – the second Sherlock Holmes book to be published and one of the four full length novels – he is described by John Watson as a “ugly long haired, lop-eared creature… brown and white in colour, with a very clumsy waddling gait.”
Toby’s actually Mr Sherman’s dog, who keeps a menagerie of creatures at No. 3 Pinchin Lane in Lambeth. Toby lives at No. 7 within his house. In The Sign Of The Four, Holmes says he would “rather have Toby’s help than that of the whole detective force in London” and requests the dog by name.
In the novel, Sherlock Holmes and Dr John Watson try to defeat a peg-legged man and his dwarf assistant. During the investigation, Holmes notices signs on creosote at the scene of the murder.
Toby, following the smell, leads Holmes and Watson to a small wooden wharf where evidently the men took a boat, leading the detective a step closer to solving the case.
Among other notable apparitions, Toby is featured in the novel Sherlock Holmes vs Dracula by Loren D. Estleman, when Watson and Holmes called on Toby to track Count Dracula after finding him in a meat-packing district.
Toby also appears in the NHK Sherlock Holmes puppet show, where he is kept by Sherman – a Baker House pupil – in a shed in Beeton School and assists Holmes in his investigation. In the series, Sherman is able to communicate with animals, unlike Mr Sherman in “The Sign of the Four”.
A dog is also featured in the Guy Ritchie’s Sherlock Holmes films, but the similarities with Toby are very narrow. Gladstone its name, it’s clearly an English bulldog and technically belongs to Watson. Sherlock doesn’t use it as a partner of investigations, but as a subject for his experiments, especially those involving narcotics. From there the running gag in the films “He’s killed the dog again!”
Finally, in the BBC series Sherlock, in the first episode of the fourth season titled The Six Thatchers, Sherlock Holmes requires the services of a bloodhound named Toby.