Modern immunology has been notably free of public disputes over credit for major discoveries in this discipline. But the early recognition of the lymphatic system witnessed two examples of heated priority feuds. The first in the 17th-century concerned the greater anatomical organization of the system, while the second in the 18th-century concerned its function. This essay reviews the earlier of the two disputes, in which a Swedish medical student (Ole Rudbeck) charged a respected Danish Professor (T. Bartholin) with plagiarism and antedating his observations. Thus ethical issues in immunology predate modern times. How this discipline reached this point in its history is another focus of this essay and also an excuse to review briefly the anatomy of the lymphatic system. The influence of nationalistic pride on priority disputes is also discussed.