SPIROCH^TES 259 



Pseudopod projection is less active than that of E. histolytica but more so than E. 

 coli. There is no distinction between endoplasm and ectoplasm and the nucleus is 

 indistinct. Encysted forms are very rarely seen and these do not show evidence of 

 reproduction. 



FLAGELLATA (MASTIGOPHORA) 



In this class of protozoa the adults have flagella for the purposes of 

 locomotion and the obtaining of food. 



Some flagellates more or less resemble rhizopods in being amoeboid and in having 

 an ectoplasm and an endoplasm. The body is frequently covered by a cuticle 

 (periplast). Some flagellates have a definite mouth part, the cytostome, which leads 

 to a blind oesophagus; others absorb food directly through the body wall. In addi- 

 tion to flagella, some flagellates possess an undulating membrane. All flagellates 

 possess a nucleus and some have contractile vacuoles. The flagellum may arise 

 directly from the nucleus or from a small kinetic nucleus, the blepharoplast (micro- 

 nucleus or basal granule). 



The most important flagellates of man are the hsemoflagellates. Among these 

 we may include the blood spirochsetes and the organism of syphilis, which have 

 many resemblances to the spiral forms of bacteria, together with the three genera in 

 which protozoal characteristics are marked, namely, Leishmania, Trypanosoma 

 and Trypanoplasma. In addition we have flagellates in the intestinal canal and in 

 the vaginal secretion. Some authors place the genus Piroplasma with the flagellates 

 and there has been controversy concerning the nature of certain projections from 

 these bodies. It would seem preferable, however, to consider them under the 

 Sporozoa. 



Spirochaeta 



The generic term Spirochata is applied to flagellates having a spiral 

 shape, an undulating membrane, and no flagella. This genus is one 

 about which there are two views: one, that the members belong to the 

 bacteria; the other, that they are protozoa. The absence of demon- 

 strable nucleus and blepharoplast makes them apparently vegetable in 

 nature while the variations in thickness, the fact of transmission by an 

 arthropod, and indications of a longitudinal, rather than a transverse 

 division, would indicate protozoal affinities. 



It would seem from recent investigations that both methods occur longitudinal 

 division occurring when there are few organisms in the blood and transverse at the 

 height of the infection. 



Minchin has adopted the name Spiroschaudinnia, proposed by Sambon, for the 

 parasitic blood spirochaetes. 



Spirochsetes of Relapsing Fevers. Relapsing fevers are caused by 

 organisms generally considered as protozoal in their nature and be- 

 longing to the flagellates. 



