viii CONTENTS 



CHAPTER IV. 



CONJUGATION, MATURATION, AND FERTILIZATION. 



Fertilization by Autogamy 139 



Fertilization by Endogamy 146 



Fertilization by Exogamy 150 



Parthenogenesis 161 



Maturation in Protozoa 164 



Significance of Conjugation 171 



CHAPTER V. 



PARASITISJI. 



Structural Modifications and Mode of Life of Protozoan Parasites . . . 175 



Reproduction and the Life C3'cle 178 



Endogenous Cycle 181 



Exogenous Cycle and its Variations 187 



Sporulation in Gregarines 189 



Sporulation in Coccidia 192 



Sporulation in Myxosporidia 192 



Exogenous Life of Protozoan Parasites 193 



Air-borne Protozoa 195 



Transmission by Inheritance 196 



Transmission by Intermediate Hosts 198 



Effects of Protozoan Parasites on Their Hosts 201 



Protozoa and the Cancer Problem 204 



CHAPTER VI. 



THE PATHOGENIC FLAGELLATES. 



The Genus Spirocheta and its Allies 217 



Spirocheta Balbianii 220 



The So-called Flagella of Spirochetes 223 



The Spirochete Nucleus 225 



Division of Spirochetes 226 



Form Changes and Life History 228 



Are Spirochetes Protozoa or Bacteria? 231 



CHAPTER VII. 



THE P.ATHOGENIC FLAGELLATES (CONTINUED). 



The Genera Herpetomonas and Crithidia 233 



Herpetomonas Donovani and Kala Azar 238 



The Genus Crithidia 241 



