I have elsewhere dealt with this point in discussing the special emotional tone of red (Havelock Ellis, "The Psychology of Red," Popular Science Monthly, August and September, 1900).
It is probable that the motive of sexual murders is nearly always to shed blood, and not to cause death. Leppmann (Bulletin Internationale de Droit Pénal, vol. vi, 1896, p. 115) points out that such murders are generally produced by wounds in the neck or mutilation of the abdomen, never by wounds of the head. T. Claye Shaw, who terms the lust for blood hemothymia, has written an interesting and suggestive paper ("A Prominent Motive in Murder," Lancet, June 19, 1909) on the natural fascination of blood. Blumröder, in 1830, seems to have been the first who definitely called attention to the connection between lust and blood.
Féré, Revue de Chirurgie, March 10, 1905.