Distribution and role of lymph vessels of the bursa Fabricii.

The fine distribution of lymph vessels in the bursa of Fabricius and the efferent lymph vessels coming from the bursa were demonstrated. The lymph vessels never entered lymphoid follicles, whereas the blood vessels pierced the cortex of lymphoid follicles and formed a network at the boundary between the cortex and medulla of lymphoid follicles. The lymph vessels commenced in the immediate exterior of lymphoid follicles. A large number of lymphoid cells were found in the lumen of the lymph vessels. Migration of lymphoid cells from the cortex of lymphoid follicles to the lymph vessels was also observed. Therefore, it was assumed that the lymph vessels of the bursa are important in the transport of lymphoid cells from the bursa to the blood stream.