152 



may therefore be carried oul under greal difficulty and against great re- 

 sistance, al 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 to a distance of 5 mm. 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 case, radiated 

 from the very small central mass. In all cases the only requisite was t lie 

 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. 



