1913. 



PUBLIC DOCUMENT — No. 31. 



55 



there is practically no difference in the development of the cut- 

 tings, whether the jars were charged with the gas every second 

 day, every fourth day, etc. (Fig. 2). 



The duration of these experiments was from one to two 

 months. In some instances the plants showed more or less 

 advanced symptoms of gas poisoning at the close of the experi- 

 ment, and the oftener the water was charged with gas the 

 quicker the symptoms appeared and the more pronounced the 

 poisoning. The same stimulating effects were shown on the roots 

 as on the stems and leaves. 



Table II. gives the results with both shoots and roots as deter- 

 mined by the average length, as follows : — 



Table II. — Showing the Stimulating Effects of Illuminating Gas on 

 Willoiv Cuttings grown in Water charged with Gas. 



[Eight treated and 8 untreated cuttings used in each series. All measurements given in centi- 

 meters.] 



In this table the average length of stems and roots is given, 

 together with the per cent, gain in average length of each. Only 

 three experiments are given. It will be noticed that there was 

 considerable gain in the average' length of roots and shoots of 

 the cuttings grown in gas-charged water. 



Another similar series of experiments is shown in Table III., 

 as follows : — 



