4 



sugar-beets, and cereals, a considerably increased yield was 

 also noted in these plants. In a few instances, it appeared that 

 soil made "sick" by continuous culture of the same crop was 

 restored to productiveness by the use of carbon bisulphid. 



Apparently the only previous experiments with carbon 

 bisulphid, as a weed-destroyer, were carried out by AYalker in 

 Arkansas in destroying sassafras sprouts, and by the writer, 

 in Maryland, also on sassafras. In both of these localities the 

 chemical was found to produce the death of the plants within 

 one month. 



In using carbon bisulphid it should always be remembered 

 that the fumes, if inhaled continuously, may produce serious 

 effects upon the workmen, and also that the material is highly 

 inflammable and should be protected from accidental flames. 

 The effects of the fumes upon workmen include headache, diz- 

 ziness, hysterical excitement, and, finally, a rather serious 

 weakness, a feeble pulse and other symptoms of prostration. 

 If it is used, therefore, in the eradication of weeds, these effects 

 should be borne in mind in order to protect the workmen. 



It is obvious that carbon bisulphid, although an effective 

 means of destroying certain weeds, cannot be used economi- 

 cally in all localities. There are many steep slopes covered 

 with guavas, in which it would be a very difficult matter to 

 operate with this chemical. It is always necessary for the 

 workmen to keep to the windward, in order to avoid the 

 fumes, and in some localities the difficulty of transporting con- 

 tainers would render the method entirely impracticable. On 

 the other hand, the use of carbon bisulphid in the destruction 

 of such plants as the guava has the advantage that young 

 sprouts do not come up from the roots. The necessity of grub- 

 bing out all of the roots is thus obviated. Under such circum- 

 stances, it would merely be necessary to allow the guavas to 

 stand until they are dead, after which the trunk and large 

 roots would be removed, as is necessary in any case in clearing 

 the land. 



