24 H. B. FANTHAM. 
the return wave (previously mentioned) suddenly becomes 
the new principal wave. In other words, the whole process 
is merely a question of transverse pressure, which is first 
applied at one or other of the ends of the organism, and sets 
up waves travelling from end to end. Also the point of 
application of the principal transversely applied inward 
pressure may be suddenly altered, for the intensity of the 
force and its point of application may alternate from end 
to end. 
In the case of lashing movements probably the myonemes 
0 
Sep 
Text-ric. 4.— Catherine wheel” figure, executed by Spirochetes 
on occasions of exaggerated spiral motion—“ end-on”’ view. 
of the body surface are the principal agents, while those of 
the membrane probably dominate in the ordinary progressive 
movements of the organism. 
The exaggerated spiral movements of 8. balbianii (andl 
the same applies to 8. anodontz) were first mentioned by 
Perrin, and compared with the rotation of a Catherine wheel 
(text-fig. 4). These must result from an “end-on” view of 
the organism progressing upwards or downwards in a plane 
more or less at right angles to that of the stage of the 
microscope. I rather think that the organism is “not very 
happy ” under such circumstances, and that the spiral move- 
