An ink impregnation study of the migratory skin in the external auditory canal of the guinea-pig.

If the tympanic membrane or attic skin is wounded with a fine needle dipped in ink, ink particles are introduced into the epidermis and underlying tissue. These particles are subsequently taken up by cells in the epidermis and dermis. In this experiment the distribution of ink within the skin of ear canal was studied in nineteen guinea-pigs, one to ten days after wounding. Examination of the intact canal reveals that ink becomes distributed along a precise line from the wound to the point of desquamation. On sectioned tissue, the ink in this line is found to be mainly intracellular, initially in the epidermis, and subsequently in the upper dermis. When considered with other evidence, these results indicate that migration probably occurs in the deeper layers of the epidermis, and that it stops at the junction of the deep and superficial parts of the ear canal.