Reexamination of testicular lymphatic drainage in the rat

To clarify the route of gonadal lymph drainage in the rat we injected dilute India ink into testicular lymphatics and concomitantly replaced the entire blood volume with Ringers lactate. This technique intensified the blackness of injected lymph vessels against a background of pale, "washed out" tissues. Whereas rat testicular lymphatics may drain into regional lymph nodes, they also commonly bypass nodal tissue entirely and enter the cisterna chyli directly. This anomalous lymphatic group suggests the testis may be an immunologically privileged site.