96 EXPERIMENT STATION. [Jan. 



was by-product A, the dry mixture proving superior to the 

 wet. Our experiments with this substance also indicate that 

 any beneficial results from its use are carried over into the next 

 season, since in those plots in which this substance was em- 

 ployed in 1911 the results were noticeable in 1912. The crop 

 obtained by the use of by-product A at the rate of 500 grams 

 to 3 square feet of surface, consisted of the cleanest tubers we 

 have ever observed in a soil which was badly contaminated with 

 scab, and, furthermore, it does not appear in the least to affect 

 the growth or yield (see Fig. 1). The substance appears to 

 act slowly and continuously as a germicide, and may prove 

 even more efficient in the control of other fungi. 



