_may therefore be carried out under great difficulty and against great re- 
sistance, at least of certain kinds such as centrifugal force when applied 
laterally. In the first experiment on the study of movements when 1,738 
gravities were used for one hour, the centrifuged filaments during that 
time moved or radiated away from the center of the small mass of filaments 
equally in all directions. Actual measurements showed that the filaments 
had moved out in the usual way toa distance of 5mm. The control specimens 
had also moved 5 mm. during the same time. There was absolutely no differ- 
ence between the centrifuged specimens and the controls as to the general 
arrangement or appearance of the filaments which had, in each ease, radiated 
from the very small central mass. In all eases the only requisite was the 
presence of a very shallow film of water about the specimens. 
When the specimens were centrifuged for one hour with a force of 5,000 
gravities instead of 1,738 gravities, the amount of movement in both centri- 
fuged and control specimens was exactly the same. Both moved away in 
a radiating direction from the small central mass 5 mm. during the one hour 
of experimentation. This shows the amount of movement to be as great, 
as far as could be determined, in the presence of a force of 5,000 gravities 
as when 1,738 gravities was used. Longer periods of time than one hour, 
using 5,000 gravities, were not used, and it has not yet been investigated 
what effect, if any, this might have on the movements. 
In the third experiment, where 13,467 gravities were used, both the 
centrifuged specimens of Oscillatoria and the controls moved 2 mm. during 
the half-hour of centrifuging. So far then as experiments have been per- 
formed, it has not been found possible to stop, or apparently retard, the 
amount or kind of movements of Oscillatoria princeps by centrifugal force. 
Indiana University. 
