PLATE 6 
The two tobacco plants shown were watered with an excess of a nutrient solution 
containing no magnesia, so as to produce a leaching effect. After well-defined symp¬ 
toms of sand drown had developed, magnesium sulphate was added to the nutrient 
solution applied to the plant at right, while the plant at left continued to receive 
the magnesium-free nutrient solution. At time of photographing plant at right was; 
rapidly recovering. Note the turgidity of the leaves and the partial restoration of the * 
natural color. 
