496 Mr. H. B. Fanthara on Spirocliaeta 



more slowly. It is a matter of iudifFerence which end of the 

 body is directed forwards, for the parasite is capable of 

 suddenly reversing its direction of movement and returning on 

 its own path, apparently even in an almost exact straight line 

 or circle. I do not consider this retracing of its path to be 

 due to unfavourable environment, as suggested by Novy in 

 the case of S. Ohermeieri, for I have observed it constantly 

 taking place inside the crystalline style. The organism can 

 then travel with or against the current indifferently. A very 

 great deal of energy seems to be used in the motion of 

 the animal. The body of the organism can be distinguished 

 during motion in the case of S. Bcdhianii w'lih some difficulty, 

 but sometimes S. anodontce moves too rapidly for its outline 

 to be clearly discernible. 



Sometimes the organism appears suddenly from a deeper 

 level of the liquid under examination, and swims, or, rather, 

 spirally bores its way more or less vertically upwards. In 

 this condition it twists itself into various peculiar shapes, and 

 so resembles a Catherine wheel as described by Perrin. 



Parasites are sometimes noticed ancliored by one end to a 

 separated or shed epithelial cell (from the gut of the host) 

 lying in the gut-contents. The free end of the parasite then 

 executes violent lashing movements or intermittent flickers. 

 The free end also in such specimens may coil itself over and 

 over. S. Balbmnn, with its rounded ends, often has some 

 difficulty, apparently, in boring its way through debris or 

 obstacles in its path. It often tries to get through these 

 instead of changing its direction of motion. However, I 

 have seen it penetrate free epithelial cells and occasionally 

 appear to come out of such cells. 



S. anodontce, with its pointed ends, is capable of rather 

 more rapid motion and more easily bores its way through the 

 debris of cells floating in the gut-contents of the host. 



Spirochsetes may at times be seen vibrating in two halves 

 about their central points as nodes ; they then resemble, to 

 some extent, two tuning-forks joined by their single ends 

 and in vibration. 



Slowly moving specimens of S. anodontce may curl up one 

 end, usually the hinder end, judging by the direction of 

 motion. 



These Spirochsetes seem to move more quickly than 

 Trypanosomes, and with an added corkscrew motion. Also 

 the body of a Sj^iril/um seems more rigid than that of a 

 Spirochsete in motion, and of course flagella are present in 

 the case of true Spirilla. 



Various scientific workers — both zoologists and bacteriolo- 



