Contents

13 February 1987
Vol 235, Issue 4790

About The Cover

Dark-field photomicrograph of cerebellar angioarchitecture demonstrated after systemic administration of horseradish peroxidase in rats bearing cortical transplants. The glycoprotein permeates portions of these transplants, which lack normal barrier properties, and subsequently enters and circulates in the cerebrospinal fluid. The vasculature is highlighted by histochemical detection of protein in perivascular spaces. See page 772. [J. M. Rosenstein, Department of Anatomy, George Washington University Medical Center, Washington, D.C. 20037]