26 BOTANICAL GAZETTE [yULY 
plates, on one of which was a layer of paraffin with sections covered 
with dune sand_and ground quartz. The growth over the paraffin 
was smooth; the roots running over the sand were wavy, in some 
places producing hairs; and the one on the quartz kinked with 
more hairs (jig. 13). One root from the plant growing over quartz 
Fic. 13.—Corn seedlings growing in water in a glass jar between paraffined 
glass plates, on which was spread in the center a layer of coarse ground quartz; 0B 
the right is dune sand; on the left is clean paraffin. 
wandered into the paraffin section, curled, and developed hairs: 
This appeared at the same time as the curling of the main root and 
may have been correlated with it. A second experiment with the — 
sections horizontal also showed the laterals wavy at the same time 
that the main root kinked on the quartz. 
WATER CONTENT. 
According to several investigators (WIESNER 88, p. 149; PFEFFER 
64, p. 100; PALLADIN 59, p. 371; BRENNER 7, p. 435; MacDoucat 
