Morphological signs as indications of function of cells in the cerebrospinal fluid.

It is suggested that a continual cell exchange exists between blood and the subarachnoid space. These cells can live for a shorter or longer time there and fulfil their function depending on local conditions. In addition to phagocytosis, morphological evidence of local cellular and humoral immunological reactions have been demonstrated and how far they concour with current views on the functional state of spinal fluid cells has been examined. Peripolesis and emperipolesis, transformation of lymphocytes as well as various cell processes, as signs of function, are illustrated by light transmission and scanning electron microscopy as well as by immunological methods in various inflammatory diseases of the central nervous system.