I found that tidbit searching under 38 special in wikipedia. The load in question was the 38/200 used by the British.

"In tests performed on cadavers and live animals, it was found that the lead bullet, being overly long and heavy for its calibre, become unstable after penetrating the target, somewhat increasing target effect. The relatively low velocity allowed all of the energy of the cartridge to be spent inside the human target, rather than penetrating completely. This was deemed satisfactory and the design for the .38/200 cartridge was accepted as the "380/200 Cartridge, Revolver Mk I".