i6o 



GENERAL BIOLOGY OF MICRO-ORGANISMS 



nates in the endoplasm near one end and passes along the border 

 of the body and finally projects as a free whip at the other end 

 of the cell. As it passes along the border of the cell it is enclosed 

 in a sheath of ectoplasm, which is drawn out into a thin sheet 

 forming an undulating membrane. Multiplication takes place 

 by approximately longitudinal division. Leishmania includes a 

 few parasitic forms, for the most part living inside the cells of 

 the host. These organisms are oval, about 2 X3M. without fla- 



E F G H I 



Fig. 79. — Endamoeba coli (Losch). A to C, Various forms of the free ameba. 

 D, Stage with eight nuclei. E to 6", Cysts with various numbers of nuclei. H, 

 Opening cyst. I, Young amebaB escaped from a cyst. {From Dofiein after Casa- 

 grandi and Barbagallo.) 



gellum or undulating membrane. In artificial culture outside 

 the body, the protozoon grows larger, develops a flagellum and 

 resembles a trypanosome. Trichomonas includes pear-shaped 

 organisms 4 to 30/i in diameter, provided with three or four fla- 

 gella. Isogamic and autogamic fertilization have been described, 

 and cysts containing numerous daughter cells result from the 

 multiplication following this process. Lamhlia resembles tricho- 

 monas, but the cell is here shaped more like a beet, is provided 



