CHAPTER IV 



PROTOZOA {cOXTIXUED): SPOKOZOA^ 



II. Sporozoa. 



Protozoa parasitic in Metazua, usually intracellular for at 

 least part of their cycle, rarely possessing pseudopodia, or flagella 

 {save in the sperms), never cilia; reproduction hy hrood formation, 

 often of cdternating types ; syngamy leading up to resting spores 

 in which minute sickle-germs are formed, or unknown {Myxo- 

 sporidiaceae). 



This group, of which seven years ago no single species was 

 known in its complete cycle, has recently become the subject of 

 concentrated and successful study, owing to the fact that it has 

 been recognised to contain the organisms which induce such 

 scourges to animals as malarial fevers, and various destructive 

 murrains. Our earliest accurate, if partial knowledge, was due to 

 von Siebold, Kolliker, and van Beneden. Thirty years ago Eay 

 Lankester in England commenced the study of species that dwell 

 in the blood, destined to be of such moment for tlie well-being of 

 man and the animals in his service ; and since then our knowledge 

 has increased by the labours of Manson, Eoss and Minchin at 

 home, Laveran, Blanchard, Thelohan, Leger, Cuenot, Mesnil, 

 Aime Schneider in France, Grassi in Italy, Schaudinn, Siedlecki, 

 L. and E. Pfeiffer, Dotlein in Central Europe, and many others. 



^ Several monographs of the group have been published recently dealing with 

 the group from a systematic point of view, including their relation to tlieir hosts. 

 Wasielewski, " Sporozoenkunde " (1896); Labbe, "Sporozoa" (in Ticrrcich, 1899). 

 Doflein's " Protozoen als Parasiten und Krankheitsevreger " (1901) contains most 

 valuable information of the diseases i>roduced by these and other Protozoic hosts. 

 Minchin's Monograph in Lankester's Treatise on Zoology, pt. i. fasc. 2 (1903), is a 

 full account of the class, and admirable in every way. 

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