200 



CAMPBELL'S SOIL CULTURE MANUAL 



a branch root showing the cell formation; from these outei 

 cells are the hair roots or feeders A A, running through 



Cut No. 21 . Deep Cultivation. 



among the particles of soil represented by the dark spots; 

 around these spots are lines parallel with the shape of the 

 particle of soil which represent the film or covering of 

 water. The white spots represent air spaces. Now, if 

 the reader will look at this cut and think for a moment 

 that these hair roots or little tubes marked A A in their 

 full size in the soil are barely perceptible to the naked eye, 



