CONTRIBUTIONS TO EMBRYOLOGY, No. 42. 



FORMATION OF MACROPHAGES BY THE CELLS LINING THE 



SUBARACHNOID CAVITY IN RESPONSE TO THE STIMULUS 



OF PARTICULATE MATTER, 



BY CHARLES R. ESSICK, 

 Captain, Medical Corps, U.S. Army, Army N euro-surgical Laboratory, Baltimore. 



With one plate. 



377 



