CHEMICAL DATA. 



13 



SULPHUR TRIOXID CONTENT OF THE FOLIAGE OF FUMIGATED AND 

 NONFUMIGATED PLANTS. 



COMPILED DATA. 



The next point to determine is whether treating these plants with 

 sulphur dioxid increases the sulphur trioxid content of the leaves so 

 that it is present in larger quantities in the treated plants than in the 

 untreated ones. As a necessary consequence of such an increase the 

 sulphur trioxid content of the ash of a fumigated plant would be apt 

 to be higher than the sulphur trioxid content of the ash of an unfumi- 

 gated plant. This can be determined by making analyses of fumi- 

 gated and control plants. 



In the work of von Schroeder and Schmitz Dumont, which has 

 already been mentioned, a chemical analysis of the pine needles of 

 the fumigated and control plants was made and the following results 

 obtained : 



TABLE 1. Comparison of analyses of pine needles from plants variously treated 

 with sulphur dioxid and from a control plant (J. von Schroeder and W. Schmitz 

 Dumont). 



It will be noted that the sulphur trioxid of the treated plants is in 

 excess of that in the untreated plant, and that the percentage of sul- 

 phur trioxid in the ash of the treated plants is higher than the per- 

 centage of sulphur trioxid in the ash of the control plant. This 

 increase in the case of (c), where only the earth was treated, is un- 

 doubtedly due to the increased amount of sulphur trioxid in the soil. 



In the experiment before mentioned, in which pines were treated 

 583 times with 1 part of sulphur dioxid to 1,000,000 parts of air, the 

 following results were obtained on subjecting the needles to a chem- 

 ical examination. 



TABLE 2. Analyses of injured and uninjured needles on fumigated pines, com- 

 pared with those of the control plant (j. von Schroeder and W. Schmitz 

 Dumont). 



Sulphur trioxid. 



