Abstract
Lymphoid nodules were f o und in the thymus of 9 out of 145chickens during the course of normal growth. Nodules first appeared in the 5th week of life. Histologically these nodules consisted of lymphocytes of various sizes, cells in mitosis and reticulum cells. They closely resembled lymphoid nodules in the spleen and the tonsilla caecalis.
The possibility is discussed that the formation of lymphoid nodules in the thymus of the chicken is bursa-dependent and that the appearance of such thymic nodules may represent a close relationship to immune responses.
