B. P. I.— 341. 



THE SOURCES OF ARSENIC IN CERTAIN 

 SAMPLES OF DRIED HOPS: 



By W. W. Stockberger, Expert, Drug-Plant Investigations. 



INTRODUCTION. 



For several years considerable attention has been given in England 

 to the question of the origin of the arsenic sometimes found there 

 in beer. & Some students of the question have pointed out glucose, 

 malt,^ and hops € as possible sources of this substance. The occasional 

 detection of minute quantities of arsenic in dried hops has furthered 

 the belief that hops should be carefully examined for traces of this 

 undesirable substance, a view which finds partial support in some 

 experiments made with hops dried by each of the two processes used 

 in England/ In one of these, known as the " direct " process, the 

 hops are dried over open fires and are thus exposed to all the com- 

 bustion products arising therefrom. In the other, or " indirect " 

 process, a current of pure heated air is caused to pass through the 



°The growing and curing of bops has been a subject of investigation in the 

 Bureau of Plant Industry during the past two years by the office of Drug-Plant 

 Investigations, under the direction of Dr. Rodney 'H. True, Physiologist in 

 Charge. The execution of the work in both field and laboratory has been 

 chiefly in the hands of Dr. W. W. Stockberger, Expert. In connection with 

 these investigations, that phase concerning the occurrence of arsenic in hops 

 has been touched upon with fruitful results, which are here summarized. Since 

 the conclusions reached have an important bearing on matters of considerable 

 economic importance, their immediate publication is deemed desirable. — B. T. 

 Galloway, Chief of Bureau. 



6 Royal Commission on Arsenical Poisoning, London, 1901-1903. Report of the 

 Medical Officer of Health for the City of London, No. 86. 



c Windisch, W. Wochenschr. f. Brauerei, vol. 18, p. 30, 1901.— Hantke, E. 

 Letters on Brewing, vol. 1, pp. 16-21, 1901. — Petermann, A. Ann. Sci. Agron., 

 vol. 2, p. 396, 1901. 



d Chapman, A. C. Analyst, vol. 26, p. 10, 1901.— Fairley, T. Analyst, vol. 26, 

 p. 177, 1901; Pharm. Jour., vol. 65, pp. 634, 738, 1900. 



e Baker, J. L., and Dick, W. D. Jour. Soc. Chem. Ind., vol. 23, p. 174, 1904. 



f Duncan, C. County Analyst's Annual Report to the Worcestershire County 

 Council, 1905, Appendix I, pp. 22-24. 



121— iv 41 



