244 BOTANICAL GAZETTE [APRIL 
with a gasometer of oxygen, and had a finely perforated mem- 
brane closing the upper end through which the oxygen was 
allowed to bubble slowly up toward the roots. The root tips 
were kept not more than 5™" from the membrane. Of 87 seed- 
lings thus supported, only 14 grew even approximately straight. 
In a third method, seedlings were supported in a Novy jar 
containing filtered water saturated with oxygen under an atmos- 
phere of pure oxygen. After the water had been saturated, the 
Fic. 1.—A, chamber containing air; B, chamber containing CO,; a, seedling 
supported on wooden bar; 4, rubber stopper; c, parchment membrane; 4d, strip of pine; 
é, small piece of rubber tubing. 
cover was slightly lifted to avoid confining the stems in an atmos- 
phere of pure oxygen. Every four hours the seedlings were 
transferred to another Novy jar of water saturated with the same 
as. A control experiment was prepared with the same number 
of seedlings in ordinary filtered tap-water. There was no appar- 
ent difference in the behavior of the roots in two preparations. 
Of 25 seedlings used in the first preparation, 7 only were growing 
straight at the close of the thirteenth hour. 
Evidently, from these experiments no proofs have been found 
to justify Molisch’s hypothesis that roots of Zea Mays in their 
curving in water are turning from a position in which the water 
is poor in oxygen to a position in which it is richer in that gas. 
