The 1951 is mostly unchanged except for illustrations showing attacker and defenders in 1951 clothes.
http://bartitsuclubofchicago.com/the-lifes-work-of-percy-longhurst/
Percy William Longhurst (1874-1959) was a lifelong wrestling and antagonistics enthusiast, a prolific writer and a significant figure in the history of Bartitsu.
Unfortunately, comparatively little is known of Longhurst’s biography, especially his early life. As an adult he served the National Amateur Wrestling Association of Great Britain in various official capacities, including Treasurer, Secretary and President. In 1899 he won the English Light-Weight Wrestling Competition and, in the same year, became one of the very first European-style wrestlers to challenge E.W. Barton-Wright’s Japanese jiujitsuka. Losing both experimental matches, Longhurst became an enthusiastic proponent of Japanese unarmed combat for sport and, especially, as a means of self defence.
Longhurst’s 1900 article, A Few Practical Hints On Self-Defence, and his subsequent references to having learned some jiujitsu from Barton-Wright himself, strongly suggest that he was at least a sometime-member of the Bartitsu Club in Shaftesbury Avenue. He also studied with both Yukio Tani and Sadakazu Uyenishi, but the chronology there is unclear.
Longhurst’s first major contribution to the self defence milieu was his seminal book Jiu-Jitsu and Other Methods of Self Defence, originally published in 1906 and in print, via at least ten subsequent editions, for many decades thereafter. This book is, for most practical purposes, the closest thing to a “Bartitsu manual” published in English, covering Longhurst’s idiosyncratic blend of various British regional wrestling styles with Japanese jiujitsu and also including some techniques of boxing and walking stick self defence. It remains a valuable resource towards the development of neo-Bartitsu styles.