A quote from Karin Knorr Cetina, Epistemic Cultures: How the Sciences Make Knowledge
p. 140. “The technical assistant (TA) … did not know how kill the animals properly – he put them to death by placing them in a -70 degree Celsius freezer. (Mice should be killed “humanely” by placing them on top of the cage and breaking their neck “by applying firm pressure at the base of the skull and sharply pinching and twisting between thumb and forefinger while at the same time pulling backward on the tail”; Hogan et al. 1986: 97.)
Hogan, B., F. Constantini, and E. Lacy. 1986. Manipulating the Mouse Embryo: A Laboratory Manual.