Microspira comma Schröt. Zoit. Enl. 10,000:1.
These show the volitional changeability of the body form. Drawn by artist Paul Flanderky
from tone models.
As shown in Fig. 192, when the individual rests, it takes on the shape
of a ball. This ball always seems to have a very shallow or flattened area. When the
example moves slowly, the body lengthens a bit and, along with that, also the flattened
or depressed area which, for the following reasons, is to be called a "gliding surface".
The following 4 illustrations show us how the body form changes with increasing speed of
motion, namely, the body stretches ever more. In Fig. 195, a weak helicoidal twisting begins,
involving the gliding surface. In Fig. 196 and 197, it becomes more distinct and strong. One
then recognizes on the living Zoit that its motion through fluids is helicoidal along the
gliding surface. With the resting position, the body immediately always takes on the ball
shape. A Zoit, suddenly aroused from the resting position, immediately takes on the body
form shown in Fig. 197. These physical changes are very reminiscent of leeches in water.
Among bacteria, this protozoa-like changeability of form stands entirely alone, because
even the flexibility of the Spirochaetiden seems to be of a more accidental nature, and the
apparent winding motion is, for a large part, merely the motion of a rigid spiral.