"Hunter-gatherer societies indulge in elaborate propitiation ceremonies to appease the spirits or spirit-guardians of the animals they have killed. Modern societies appear, superficially at least, to have overcome their guilt at killing animals, and yet a closer examination suggests that we might merely be hiding a deep-seated and unexamined guilt. For example, the common use of the term sacrifice in animal research may be meaningful in this regard. In kosher slaughter, the actual killing is performed by a holy man, the shochet, because he has the grace and strength of character to bear the associated guilt. In Tibet, butchers are considered outcasts." A.N. Rowan, "The Human-Animal Interface: Chasm or Continuum?" In, M.H. Robinson and L. Tiger, Editors, Man & Beast Revisited. Washington, D.C., 1991. p.281.