42 Plant Physiology 



may be based better practices in soil preparation and cul- 

 ture. Investigations upon root distribution have been 

 more extensive at some of the experiment stations in the 

 West, and there are very few data available for conditions 

 in the United States essentially different. Ten Eyck has 

 shown that the roots of the corn, wheat, oats, and other 

 cereals may reach a depth of from three to four and a half 

 feet, the small grains reaching the greater depth. His 

 method consists in supporting the cuboidal mass of soil 

 containing the roots in wire-netting cages, through the 

 meshes of which many steel rods are thrust horizontally. 

 When the soil is washed away, the roots do not break so 

 readily as when unsupported. Nevertheless, this method 

 has many difficulties and involves special apparatus for 

 handling large quantities of earth. 



Recently a method has been developed in Russia by 

 Rotmistrov whereby the difficulties experienced in han- 

 dling large quantities of soil are to a considerable extent 

 eliminated. Some new sources of error have been intro- 

 duced, but apparently the work has been as well controlled 

 as possible. The method consists in growing plants in the 

 natural top-soil and sub-soil compacted into extensive 

 narrow boxes sunken in the soil during the period of growth. 

 When placed in position, these boxes present a surface 

 1 inch wide, 20 to 40 inches long, and 20 to 40 inches or 

 more in depth. The roots eventually occupy a volume 

 of earth equivalent in form to that of a narrow slab or 

 broad board. After the desired period of growth it is 

 possible to obtain practically the exact form of the entire 

 root-system by the manipulation suggested. Practically 

 speaking, this consists in the inversion of the root-pene- 



