| Summary: | Thesis (M.A.)--Boston University === Preliminary observations were made on the reactions of the cellular and vascular elements of the retrolingual membrane of the frog's tongue to stimulation by certain foreign particles. The technique of Pratt and Reid (1930) was used in preparing the membrane. Microscopic drops of irritants, croton oil and turpentine, and a non-irritant, cedar oil, were applied from a micropipette, using the Emerson micro-manipulator, to the different experimental membranes. Non-irritating substances, neutral red, trypan blue, and India ink were injected into the abdominal cavity of frogs in successive experiments. Responses to each of the substances were compared with the condition in the normal membrane.
The ciliated epithelium responded to all stimulation except the neutral red. Vacuoles of trypan blue were found in these cells. There vrere many carbon granules in the membranes
of frogs treated with India ink. Both the cedar oil and croton oil were lifted from the membrane by the ciliated epithelial cells, with cilia beating. There was no evidence of phagocytosis of the cedar oil, but pink vacuoles appeared in the ciliated cells of the croton oil preparation. When croton oil with Sudan III was placed on the membranes of frogs previously injected with trypan blue, epithelial cells with active cilia and large blue vacuoles removed the drop from the surface and phagocytized some of the oil. Phagocytosis of the dye did not incapacitate these cells for further ingestion of foreign particles. Other substances should be used experimentally to determine the extent of the power of phagocytosis by the epithelial cells of the retrolingual membrane of the frog.
Histiocytes phagocytized neutral red and India ink. Their only response to irritants was migration toward the substance. Leucocytes phagocytized India ink. They responded to irritants by migrating from the blood stream into the tissues, but showed no evidence of phagocytizing the irritant. Further study should be made in regard to the materials phagocytized by each one of these cells.
There were no vascular changes in the membranes when non-irritating substances were used. Irritating substances stimulated blood vessels changes which followed the basic pattern of inflammation. A greater number of capillaries opened at the site of irritation; dilation of the small blood vessels occurred; the permeability of the endothelium was increased, as demonstrated by stasis and the migration of leucocytes from the blood vessels.
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