15 



SPECIAL PART 



I. REPRESENTATIVE PARASITIC PROTOZOA 



IMPORTANT GENERAL REFERENCES 

 Calkins, '09; Castellani and Chalmers, '10; Crawley, '12; Doflein, '09; 

 Lankester, '03; Manson, '07; Ward, '08. 



INTRODUCTION 



Parasitic Protozoa — Importance for years overlooked. Pasteur's, 

 '38, study of the protozoa causing silkworm disease had great in- 

 fluence on development of germ theory of disease. In 1880, Laveran 

 discovered the malarial parasite, but it was not until the beginning' 

 of the present century that much attention was devoted to parasitic 

 Protozoa. 



Groups of Protozoa concerned — Parasitic forms now known in all 

 groups except Radiolaria and Foraminifera. 



Habitat — Organ, tissue, and cell parasites, — even nuclear parasites 

 known. 



Adaptations — Comparable to those seen in other parasitic groups. 



Sub-Phylum SARCODINA 



Entamoeba dysenterise — Amceba coli Losch; Entamoeba hystolytica 

 Schaudinn). Supposed cause of a type of tropical dysentery. 

 Since Lambl, 1859, amceba known to occur in human intestine but 

 pathogenic nature disputed. Since work of Schaudinn, '03, known 

 that there are two species; one, at least, pathogenic. See, Strong, '07. 



Habitat — Human colon, intercellular; occasionally lower part of 

 small intestine and even liver. Walls of intestine greatly thickened 

 and, in serious cases, ulcerated. 



Structure — Essentially that of Amoeba (see p. 11); one or two 

 pseudopods; endosarc granules, frequently containing red blood cor- 

 puscles; nucleus eccentric, with sparse chromatin. 



Reproduction — Two types: 1st, simple division, or budding; 

 2d, by encystment and spore formation. Autogamy. Method of 

 dissemination of the parasite. 



Prophylaxis — Heat sterilization of food and drinks. 



