LUTHER BURBANK 



gained with the aid of the microscope and the stud- 

 ies of the chemist, we shall quickly come to under- 

 stand why it is that water plays this all-important 

 part in the functions of plant life. For it appears 

 that the essential basis of life itself, namely, pro- 

 toplasm, is a substance composed largely of water 

 and having the physical constitution of a viscid 

 liquid. 



We find, moreover, that no particle of solid 

 matter can, under normal conditions, penetrate the 

 walls of the cells that make up the minute com- 

 partments in which the individual masses or pro- 

 toplasm lie. 



Ramifying everywhere among these are spaces 

 and tubules that convey water and air. And por- 

 tions of this water and air are absorbed by the bits 

 of protoplasm through their cell walls. 



With the water they gain the mineral constit- 

 uents that are essential for their nourishment. But 

 these include no minerals that are insoluble. 



It is true that the plant rootlets may on occa- 

 sion secrete certain fluids that aid the water in 

 bringing into solution some intractable chemicals. 

 But these secretions themselves are watery fluids 

 and they would be ineffective if there were not 

 water present to complete the work that they begin. 



In a word, then, the all-essential element for 

 which provision must be made by the gardener or 



[14] 



