PLANTS AND OTHER CONSmERATIONS 65 



strong argument for utilizing a standard synthetic 

 water for many of the tests done now in whatever wa- 

 ter happens to be available. 



In many cases the investigator is primarily inter- 

 ested in the eflFect of toxicants or other factors under 

 local water conditions. If such is the case he will use 

 local water even though the resulting observations 

 may not be comparable to those based on work in 

 other waters. In such a situation it would be desirable 

 to run duplicate tests utilizing a standard or recon- 

 stituted water for one and local water for the other. 



