CHAPTER I 



THE BIOLOGY OF HOST-PARASITE RELA- 

 TIONS BETWEEN MAN AND HIS 

 INTESTINAL PROTOZOA 



I. Introduction 



I. Protozoology 



Protozoology is a subject of interest to students of 

 various branches of biology. It is taught in the zoology 

 departments of many colleges and universities and in 

 medical schools, especially in schools of tropical medicine. 

 Investigations in this field are carried on principally by 

 zoologists and medical men. Zoologists who are inter- 

 ested in protozoology usually direct their attention pri- 

 marily to the parasite, whereas most medical men tend 

 to emphasize the reactions of the host. The zoological 

 protozoologist, for the most part, is concerned with 

 morphology, systematics, and life-history studies, and the 

 medical protozoologist with symptomatology, pathology 

 and therapeutics. Only when these two phases of the 

 subject are brought together and studied experimentally 

 and when the aspects of the subject peculiar to public 

 health activities are added is a complete program real- 

 ized; then protozoology becomes the Biology of Host- 

 Parasite Relations. 



