Properties of a Myxomycete Plasmodium. 181 
In ascertaining the latter fact, a strip of blotting-paper, cut 
as indicated in Woodcut 3, had the united lower ends placed 
in contact with the plasmodium which was spreading upon 
wood. One arm of this syphon was placed in distilled, the 
other in hydrant-water, and in repeated trials the plasmodium 
showed no choice between the two currents, so that, every 
other factor being eliminated, it can be stated positively that 
Woodcut 3. 
this movement of plasmodium is due to rheotropism alone, 
and not to substances contained in the water supplied to it. 
For the experiments designed to test the force of the 
current against which the plasmodium is positively rheotropic, 
wood upon which the substance was creeping was suspended 
so that the plasmodium just skimmed the surface of the 
water, which two-thirds filled a glass pan nine inches in 
diameter. The pan was caused to revolve with uniform 
