The study of the lymphatic system still remains far from completed. The question of the relation of the lymphatics to the two most important systems of the animal body, the central nervous system and the bone marrow system, has been especially obscure. There has existed a widespread opinion that the brain is entirely lacking in independent (not perivascular) lymph channels. Unbelievable as it is, that the lymph circulation in the most delicate tissue in the body—the brain substance—is dependent for its metabolism on the perivascular lymphatics, this opinion was supported by such authorities as His1 and Retzius. Bevan Lewis2 was the first to raise the question of an intervascular lymphatic system, independent of the perivascular and intravascular systems; once raised, this question never disappeared from the literature until Meynert proved clinically and Kronthal3 morphologically that there are lymphatics of the cortex of the brain independent of