“Touch’ is a multi-faceted concept, reflecting the different types of receptors. The simplest are free nerve endings which detect pain and changes in temperature; slightly more complex are Merkel’s tactile cells (which detect pressure); followed by Grandry bodies, which consist of two to four tactile cells and detect movement (velocity); and the lamellated Herbst corpuscles (similar to Vater-Pacinian corpuscles in mammals), which are sensitive to acceleration.”