86 EXPERIMENT STATION. [Jan. 



ment and remedies it matters little whether there is one organ- 

 ism or two associated with the disease. In either case remedies 

 are based on the same principle, i.e., the disease is cansed by a 

 pathogenic organism and is infectious. 



Professor Bolley ^ later developed a method for preventing 

 the scab which has proved quite effective, at least under certain 

 conditions. This method consists in soaking the seed potatoes 

 in a solution of corrosive sublimate, 23 ounces to 15 gallons, 

 for a period of one and one-half hours. This is to destroy the 

 germs on the seed potatoes, and when this treatment is ai:)plied 

 with such necessary precautions as the avoidance of stable 

 manures, etc., it has proved effective, at least when the organ- 

 isms are not especially abundant in the soil. Experiments with 

 corrosive sublimate were also carried on for three years by Dr. 

 J. C Arthur,^ and in the meantime both Professor Bolley and 

 Dr. Arthur were experimenting with formalin, Professor Bol- 

 ley ^ as a remedy for the smut of wheat, oats and barley, and 

 Professor Arthur as a remedy for the scab. Professor Arthur ^ 

 later published his experiments with the use of formalin as a 

 preventive of potato scab. lie shows that formalin (40 per 

 cent, solution), used at the rate of 8 ounces to 10 gallons of 

 water, is effective and equal to corrosive sublimate, besides pos- 

 sessing fewer disadvantages in handling. Corrosive sublimate 

 and formalin have now been in use for many years as a pre- 

 ventive of potato scab, and both have been the means of greatly 

 reducing the disease. As they are designed to kill the organisms 

 on the surface of the tuber and not those in the soil it is always 

 necessary to use other measures to accompany the treatment 

 with the chemicals. Dr. Thaxter from the first recognized the 

 necessity of using clean seed potatoes and the avoidance of stable 

 manures. 



Dr. B. D. Halsted ^ has experimented with various substances 

 for the control of potato scab, and he has reported especially 

 favorable results from the use of flowers of sulfur applied to 



• H. L. Bolley, Bui. 4, North Dakota Agr. Exp. Station, 1891; also Bui. 9, 1893, pp. 19-95. 

 ' J. C. Arthur, Bui. 56, Purdue Univ. Agr. Exp. Stcation (Ind.), 1895. 



3 H. L. Bolley, Bui. 19, N. D. Agr. Exp. Station, 1895; also Bui. 27, 1897, and Bui. 37, 1899. 



* J. C. Arthur, Bui. 65, Purdue Univ. Agr. Exp. Station (Ind.), 1897. 



6 B. D. Halated, Bui. 112, N. J. Agr. Exp. Station, 1895; also Bui. 120, N. J. Agr. Exp. Station, 

 1897. 



