THE EFFECT OF HYDROGEN PEROXIDE. 379 



Table 2 shows the results of the treatment of oats in the season of 1914. 

 The effect of hydrogen peroxide in these tests was positive in every case. 

 Although smut was eliminated entirely only in one case (plat 19), there 

 was a considerable reduction of it on practically every plat, especially where 

 the seed was treated with stronger solutions (plats 13 to 19). According to 

 the tabulated results the average per cent, of smut on nineteen plats treated 

 with hydrogen peroxide solution was 4.9, and 11.0 per cent, on the check 

 plat. 



The tests made in the season of 1915, in which only four different strengths 

 of solution (1 to 100, 1 to 75, 1 to 50, 1 to 25) were used and the time of 

 soaking was increased to five hours, showed practically the same results as 

 the tests of the preceding season. Although the percentage of smut in this 

 crop was only two per cent., the effect of the hydrogen peroxide treatment 

 was quite apparent in all but one case. While the plat treated with 1 to 100 

 solution produced two per cent, of smutted stalks the other pl.ats showed 

 almost a uniform decrease in the amount of smut from two per cent, to six- 

 tenths of one per cent. 



In summarizing the results of these tests it may be stated that weaker 

 solutions of hydrogen peroxide, varying in proportion from 1 to 100 to 1 to 

 25, not only had no effect in preventing the stinking smut of wheat but even 

 seemed to stimulate its development and considerably increase its quantity 

 in the crop. Stronger solutions, however, varying in strength from 1 to 15 

 to pure hydrogen peroxide, had perceptibly decreased the amount of wheat 

 smut, the pure solution reducing it from sixteen per cent, to three and one- 

 tenth per cent. In the case of oats, however, there was a gradual reduction 

 of the smut disease in most cases, and a complete elimination of it when seed 

 oats were soaked thirty minutes in full strength hydrogen peroxide. 



The five-hour period of soaking the seed apparently had no more pre- 

 ventative effect on the development of smut then the one-hour period. The 

 one-hour period was more effective in most cases than the thirty-minute 

 period; and the latter produced better results than the fifteen-minute period. 



Hydrogen peroxide had no retarding but rather stimulating effect on the 

 germination of both wheat and oats. 



Inasmuch as only pure hydrogen peroxide will materially reduce the 

 stinking smut of wheat and entirely eliminate the smut of oats, as indicated 

 by the results of these tests, the high cost of the treatment makes its practical 

 application prohibitive. Formaldehyde furnishes not only a more effective 

 but also the cheapest seed grain disinfectant. 



All hydrogen peroxide used in this work was furnished by the Commercial 

 Company, Clearing, Illinois, at whose suggestion the tests were made. 



A brief reference to this work has been made in the twenty-seventh and 

 the twenty-eighth Annual Reports (pp. 32-33, and p. 30, respectively) of 

 the Purdue University Agricultural Experiment Station. 



