0«t 



In conclusion^ It is probable that the roots 

 of some plants do, and must, respire aerobically. It is 

 probable that good soil aeration is generally beneficial, 

 both directly and indirectly. There is no evidence in- 

 dicating that these rules are absolutely general. Indeed, 

 it is probable, by analogy at least, that some plant 

 roots can live anaerobically and that some soils are 

 more favorable than others to such anaerobic existence. 



