Microorganisms and Planf Life 193 



promising but are as yet little known. The attention given 

 to the effects of antibiotics on plants and plant diseases is 

 slight compared to that given to their effects on animals 

 and animal diseases. 



Concluding Remarks 



In this paper, some of the varied relationships between 

 microorganisms and higher plants have been indicated, 

 and some of the limits of information regarding these re- 

 lationships have been pointed out. From even a cursory 

 consideration, it is evident that the relationships are nu- 

 merous and diverse. A comprehensive discussion would in- 

 clude many types of associations not mentioned at all here. 

 Although something is known of many types of associations, 

 knowledge of many, and indeed of most of them, is limited. 

 The lack of information concerning the reactions involved 

 and the factors affecting the associations might well serve 

 as a challenge for present and future investigators. 



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