ANDREWS & BEALS: GROWTH OF ZEA Mays 97 
I liter of air; B, 3 liters; C, 92 liters; D, 120 liters; and E 144 liters 
in 24 hours. The figure shows that the plants made better growth 
when an increased amount of air was used. 
The temperature of the culture solution was often too high for 
good growth. Fic. 3, A, is a culture grown without aérating or 
having the temperature lowered to a favorable point. B is a cul- 
ture which was aérated with about 48 liters of air in 24 hours, but 
whose culture solution was above a favorable temperature. Cisa 


-E D Cc B A 
Fic. 2. Effects produced by different quantities of air passed through the cul- 
ture solution. Reading from right to left: A received 1 liter in 24 hours; B, 3 liters; 
C, 92 liters; D, 120 liters; and E, 144 liters. 
culture which was aérated with about 48 liters of air in 24 hours 
and which in addition had the temperature of the culture solution 
lowered to a favorable point. The temperature in the culture 
solution of C was controlled by placing the glass cylinder contain- 
ing the roots in a large vessel and allowing a sufficient quantity 
of water of the desired temperature to flow around it. It is at 
once seen from the photograph, Fic. 3, that B has grown much 
better than A, and that C is much larger and has grown faster 
than B. All the cultures were started at the same time and all 
