Blue-black Pigmentation Research Articles

The Development of Melanophores in the Down Feathers and Skin of the Silkie Fowl

INTRODUCTIONACCORDING to Weidenreich (1912) numerous pigment cells occur in all the deeper parts of the body as well as in the skin of the lower classes of vertebrates. In birds and mammals, there has been a progressive reduction of the visceral pigment cells, with the result that the largest accumulations of melanin are generally confined to the epidermis alone, more specifically to derivatives of the epidermis such as feathers and hair. However a notable exception to this rule occurs in the Silkie fowl.At least 5 varieties of Silkie fowl have been produced by selection. These are the White, Black, Blue, Gray and Partridge Silkies. In addition to the characteristic feather color all varieties possess gross blue-black pigmentation of the dermis, subcutaneous tissues, parietal and visceral peritoneum, periosteum and perichondrium. Pigment cells are also found in abundance in close association with the blood vessels, in the membranes of the .

141. A Pigment-producing Organism (Pseudomonassp.) Isolated From Discoloured Butter

An organism, isolated from discoloured areas in butter and capable of reproducing the colour in artificial culture, is described.A brown colour, which may probably be attributed to the action of ammonia produced by this organism, diffused through the medium.A blue-black insoluble pigment, produced only at low temperatures, was concentrated in and around the bacterial cells. The nature of the source of nitrogen influenced the development of this pigment, proteose appearing to be inhibitory.NaCl in moderate concentration was usually necessary for growth.