LUTHER BURBANK 



importance. Yet in the last analysis the constitur 

 tion of the soU — the very existence of the soil it- 

 self — is of incidental or subsidiary significance 

 only in the plant economy. The richest soil that 

 was ever prepared would not grow a single blade 

 of grass or the tiniest weed if that soil were abso- 

 lutely dry. 



Nor could the hardiest weed maintain exist- 

 ence for a single day if transplanted into a soil, 

 be it never so rich, that is absolutely devoid of 

 moisture. 



There must be water in the soil, to dissolve out 

 and transfer its elements, in order that the rootlets 

 of the plant shall be able to make the slightest use 

 of these elements. Every essential constituent of 

 plant food may be present in just the right pro- 

 portions in soil that is packed about the roots of 

 the plant with just the right degree of firmness, 

 and yet the plant would perish as inevitably as if 

 it were uprooted and suspended in the air, if there 

 were not water present to bring the food materials 

 into a state of solution. 



But on the other hand, as we have seen, a plant 

 may grow and thrive for a time quite without the 

 presence of soil of any kind or quality if its roots 

 are placed in water. 



If we look a little farther into the intimate 

 structure of the plant, utilizing the knowledge 



[12] 



