1915] 



MERRILL DISTILLED WATER 



481 



were grown for purposes of comparison. The duration of 

 growth was 30 days. 



Whether the beneficial effect of the sterilization was due 

 to the destruction of the bacterial and fungous floras of the 



TABLE VII (Series 5) 



EFFECT PRODUCED ON GROWTH OF PLANTS BY STERILIZING THE WATER IN 



WHICH THEY ARE GROWN 



Culture 



no. 



1 



2 

 3 

 4 

 5 

 6 



Medium 



Dist. H 2 

 Dist. H 2 

 Dist. H 2 

 Dist. H 2 

 Full nutr. 

 Full nutr. 



Condition of 

 medium 



Unrenewed 

 Renewed 

 Sterilized 

 Sterilized 



Unrenewed 

 Renewed 



Green wt. 



of tops 



gms. 



1.55 

 1.65 

 2.40 

 3.05 

 10.30 

 17.65 



Dry wt. 



of roots 



gms. 



.141 

 .150 



.225 

 .233 

 .342 

 .507 



medium, to a decomposition of any contained toxic substances 

 (thereby rendering them less toxic), or to incidental effects 

 such as aeration of the water by the boiling process, was not 

 definitely determined. Neither was this effect compared with 

 that produced by the addition of various bodies (tannic acid, 

 pyrogallol, calcium carbonate, various hydrates, carbon black, 

 and other substances mentioned by Livingston and his co- 

 workers, '05, '07, Dachnowski, '08, '09, and others). In the 

 last paper of Livingston and his co-workers referred to 



are given the results 



of boiling the 



aqueous extracts from 



soils containing toxic properties as determined by the growth 

 of plants in the same. The boiling improved the extracts, 

 but this effect was explained by " supposing the process of 

 boiling to remove or change the toxic action of this extract, 

 the toxic materials being perhaps partly volatile with steam. ' ' 

 But since in our sterilization process a return condenser was 

 used the removal of toxic substances by volatilization would 

 not occur. A breaking down of toxic compounds into less 

 toxic constituents may possibly be a condition induced by the 

 boiling, however. It will be recalled that Lyon ('04) found 

 the toxicity of tap water reduced by boiling. 



While the oxidizing power of roots, due to enzymatic 

 activity, may be an important factor in aiding in the decom- 



