Xlbe Century Btoloaical Series 



'Kobett Degnec» BDitoc 



Host-Parasite Relations 



Between Man and 

 His Intestinal Protozoa 



BY 



ROBERT HEGNER, Ph.D. 



PR0FES80R OF PROTOZOOLOGY IN THE SCHOOL OF 



HYGIENE AND PUBLIC HEALTH OF THE 



JOHNS HOPKINS UNIVERSITY 



The Century Co. 

 New York London 



