BARIUM IN TOBACCO 27 



A number of investigations have been made in the United 

 States by the Bureau of Plant Industry and the Bureau of Soils, 

 for the detection of barium. The work in this country has been 

 done to ascertain, if possible, if the poisonous properties of the 

 Loco weed which causes the Loco disease in cattle, is due to the 

 presence of barium in the plant. 



J. S. McHargue, Journal of the American Chemical Society, 

 June, 1913, describes his work that shows the presence of barium 

 in tobacco and in various others plants. 



Many are doubtless more or less familiar with the wide distri- 

 bution of barium in soils. The old igneous rocks have disinte- 

 grated into simpler compounds which finally have become avail- 

 able as food for the growing plant. It is still a question 

 whether barium should be considered a plant food at all, although 

 it is found more or less in the vegetable kingdom, but not in all 

 the species that have been investigated. 



We have examined the leaves and stems of a number of speci- 

 mens of tobacco, grown in Sumatra, Cuba, and in various parts 

 of the United States. We desire to express our thanks to Mr. J. 

 M. Goldstein, of Oneida, New York, for kindly supplying most 

 of the specimens. 



Our method was essentially that outlined by McHargue in the 

 paper referred to. We selected twenty-five grams of the leaves 

 which were just sufficiently moist to prevent crumbling. These 

 were cut into small bits and placed under a hood as the odors are 

 very disagreeable. The combustion is made with one Tirrell 

 burner in about two hours. Too great heat is not desirable as it 

 fuses the ash and renders it more difficult to handle. The ash 

 is weighed and while in the platinum dish, it is dampened with 

 distilled water, 15cc. of hydrochloric acid is added, and it is 

 heated twenty minutes on the water bath to complete the reaction. 

 There are two conditions in which the barium seems to exist in the 

 ash — a part soluble in hydrochloric acid, and an insoluble portion 

 which is barium sulphate. The precipitate containing the barium 

 sulphate with the ashes of the filter paper is placed in a platinum 

 crucible to which are added a few drops of dilute sulphuric acid 

 and lOcc. of hydrofluoric acid. It is digested slowly for several 

 hours over a free flame. This decomposes the silicates, and the 

 residue is evaporated to dryness. Next a sodium carbonate fusion 

 is made with about four grams to decompose the barium sulphate. 



