CHAPTER III 



NOTES ON CERTAIN PARASITIC PROTOZOA 



Spiroclicetce : Spiroch&ta Ziemanni. 



WHAT is a spirochaeta ? To answer this question we must consider 

 the organisms that were first given this name. The genus Spiro- 

 chceta was founded by Ehrenberg, and the name was first applied 

 by him to the Spirochceta plicatalis, since renamed refringens by 

 Schaudinn. This is a slender organism with blunt ends and of 

 spiral form, especially when in motion ; it has a distinct undulating 

 membrane, but is apparently devoid of flagella. The nuclear struc- 

 ture extends the whole length of the body. Such an organism 

 differs from a spirillum or spiral bacterium in several ways : it is 

 flexible, having no cellulose envelope ; in the possession of an 

 undulating membrane, and in the absence of flagella. Until recently 

 the spirochsetae were regarded as being of vegetable nature, but 

 their close similarity to other organisms regarded as belonging to 

 the Trypanosomatidtz e.g., the Trypanosoma Balbianii, 1 a parasite of 

 the alimentary tract of the oyster ; one which differs from the bacteria 

 in having an undulating membrane and in its mode of division 

 being longitudinal, as in the flagellate protozoa, and not transverse, 

 as in the bacteria, raises this question, What is a spirochaeta ? one of 

 the unsolved problems left by the untimely death of Schaudinn. It 

 was first definitely raised by his study of the Sp. Ziemanni, a blood 

 parasite of birds. A brief note of Schaudinn's description of this 

 will now be given, in order that the state of our knowledge of 

 spirochaetae may be understood. 



1 A note by W. S. Perrin, Proceedings of Royal Society, August 3, 1905, may 

 be consulted on this subject. 



J9 22 



