PROPERTIES OF THE ESOPHAGEAL EPITHELIUM IN RELATION TO ORGANIZATIVE PATTERNS OF LYMPHOID INFILTRATIONS IN THE RED-EARED TURTLE

The esophagus of the turtle, like the mucosal surfaces in other specie s, contains variously sized areas of lymphoid infiltration. The tunica propria and the surface epithelial layer of this area are invaded by the lymphoid cells. The features of the layer of epithelial cells whic h cover the lymphoid infiltrations are of a special kind: they do not possess vibratile cilia and are able to take up materials flowing into the lumen. The present paper contains further information concerning lymphoid infiltration obtained by histological and histochemical metho ds. The epithelial layer covering the lymphoid infiltrations is compos ed of cells with irregularly distributed microvilli, ciliated cells an d mucous-secreting cells. After administration of silica and colloidal carbon, the microvillar epithelial cells proved to have these substan ces inside them, thereby accounting for the pinocytotic activity. The absorbing epithelial cells were not damaged by silica which is a macro phage-toxic agent, while the underlying macrophages are damaged. These results are compared with the features of lymphoid infiltration assoc iated cells in various organs and animals; the hypothesis is proposed that these cells in the esophagus of turtles may originate from the co vering epithelial cells.