Activity of the hair follicle is cyclic, periods of hair-growth alternating with periods of quiescence during which the dead hair is retained as a ‘club’. In the rat, hair-growth occurs in a series of waves which start ventrally and pass over the flanks to the back (Dry, 1926; Butcher, 1934; Johnson, 1958a).
The object of our work was to find out how far such activity is dependent upon factors within the follicle and how far it is subject to systemic control. When hair follicles are translocated, either by rotation of grafts in the mid-flank or by transposition of flaps in two stages, they continue to maintain the periodicity characteristic of their sites of origin (Ebling & Johnson, 1959). Vascularization of such follicles is always consequent upon follicular activity, even when this is out of phase with the normal waves of hair-growth on the adjacent body.