THE MELANOTIC PIGMENT IN THE SKIN, HAIR AND EYE OF THE GRAY RABBIT

Abstract

In the higher vertebrates, especially in man, most of the melanotic pigment is to be found in the ectodermal elements of the skin, where it plays a much more important rôle than the mesodermal pigment. The pigment building cells (melanoblasts) of the epidermis are the ordinary basal cells, sometimes cells lying directly above them, and cells lying at about the basal cell level but showing dendritic processes. Melanoblasts are also found in the hair matrix cells of the bulb, in the epidermal hair sheets, the epidermal parts of the sebaceous glands, the excretory ducts of the sweat and sebaceous glands and in certain mucous membranes. With the paper of Kolliker in 1860 there began a controversy that lasted for many years as to whether the epidermis built its own pigment or whether it obtained this pigment from the cutis. According to Kolliker, Aebi, Halpern, Riehl and Karg (1860 to 1891),