Intracellular membrane structures are subjected to a continuous renewal. Breakdown products are undoubtedly partly used for resynthesis locally, partly disposed of. The transport of lipoproteins is generally managed by the lymphatics ; in the brain, devoid of lymph vessels, prelymphatic pathways (substance of the basement membranes of the blood capillaries → Virchov-Robin’s intraadventitial spaces → intraadventitial spaces of cervical blood vessels → cervical lymphatics; 4) are fulfilling this task. Stasis of lymph-due lipoprotein molecules induces pericytes to incorporate them. In previous histochemical studies performed on the heart muscle, kidney, liver and intestine it has been shown that a regular consequence of lymphostasis is the appearance of ‘invisible’ lipids, derived from breakdown products of desintegrated cellular membrane structures (lipid phanerosis) . The appearance of lipid droplets in pericytes can be regarded as a cerebral equivalent to this lipid phanerosis. In later stages of lymphogenic encephalopathy, collagenous and collagen-like fibers were seen in the substance of basement membranes . Taking into account this fact and the marked alteration in lipid metabolism and the transport described above we feel justified in suspecting that lymphogenic encephalopathy may have some bearings on cerebral artherosclerosis.