The importance of basic knowledge of the lymphatic system has long been recognized by scientists throughout the world as well as by Federal meat Inspection. Thus in Circular No. 866 (U.S. Dept. of Agriculture, 1951) it is noted that "persons engaged in meat inspection should have a thorough knowledge of the lymphatic system of animals, the flesh of which is used for food." Lymph nodes play an important part in deciding the final disposition of a carcass. The M.I.D. Training Guide No. 38 (U.S. Dept. of Agriculture, 1959) underlines that "the importance of certain lymph nodes is based on location of tissues from which their afferent vessels originate."