COMMUNICATION OF THE INTRACRANIAL SPACE WITH SPHENOID BONE-MARROW IN MICE

Tritiated thymidine and Ehrlich ascites tumour cells were injected int rathecally in adult Balb/c mice. Thymidine penetrated easily into the sphenoid bone marrow, where it labelled numerous leukocytes. The micro vessel wall constituted a partly penetrable barrier against the infilt ration of Ehrlich ascites tumour cells from arachnoid space into the b one marrow. A possible physiological role of the drainage of substance s from the brain into the bone marrow is discussed.