Hoagland — 124 — Plant Nutrition 



to the increase of virus protein in an infected plant. 

 Perhaps also the student of plant anatomy and mor- 

 phology may find that he can cooperate at times with 

 workers who have experience in managing culture 

 solutions. 



One of the outstanding values of controlled culture 

 technique, no doubt, will eventually be found in the 

 studies biochemists can make on plants subjected to 

 controlled environments. I observed in the first lecture 

 that biochemistry applied to higher plants has not 

 received nearly the degree of effort it deserves, despite 

 important individual achievements. I have the im- 

 pression that artificial culture methods, including 

 climatic control in appropriate cases, as well as control 

 of nutrient media, will render important service to 

 plant biochemists. 



Concluding Statement: — In these lectures as a 

 whole the attempt has been made to survey some of 

 the problems of plant nutrition and to give a general 

 perspective of this field of inquiry. Of the limitations 

 of the discussions I am keenly aware. Plant nutrition 

 is not of itself a science. Its study rests on the appli- 

 cation of other sciences to a vastly complex system. 

 Progress is slow and laborious. There does not usually 

 exist the possibility of setting down in the precise 

 and elegant terms of the physical scientist the course 

 of events in the growing plant. 



The practical objectives form a compelling incen- 

 tive for a worker in an agricultural experiment station. 

 Our industrial civilization rests on ability to produce 

 all the food we need by the efforts of a small fraction 

 of our total number of workers. This can be accom- 

 plished only because of advances in agricultural arts 

 and sciences. Certainly one of the important scientific 

 foundations of modern crop production is knowledge 

 of plant nutrition. Still I suspect that, as in many 

 other subjects, we are led on to continued research 

 because of curiosity ; the desire to find out what plants 



