New York Agricultural Experiment Station. 1 s . 



of the method are three: (1) Simplicity; (2) freedom from danger 

 of fire; and (3) the rapidity with which the gas is liberated. 



From 1900 to 1905 Jones and Morse, 6 at the Vermont Experiment 

 Station, experimented with the disinfection of seed potatoes by means 

 of formaldehyde gas. In their early experiments the gas was 

 generated by evaporating formaldehyde solution over a flame, 

 but in 1905 they used the (then) new formalin-permanganate 

 method with promising results. In Bulletin No. 141 of the Maine 

 Station, published in March, 1907, Morse recommends the following 

 treatment as applicable where a large quantity of seed potatoes is 

 to be treated: "Place seed potatoes in bushel crates or shallow 

 slat-work bins in a tight room. For each 1000 cubic feet of space 

 spread 23 ounces of potassium permanganate evenly over the bottom 

 of a large, flaring pan or pail placed in the middle of the room. Pour 

 over this three pints of formalin. Close room at once and do not 

 open for 24 to 48 hours." 



In a later bulletin Morse 7 reports an experiment in which the above 

 treatment was successfully applied on a commercial scale. He also 

 relates the experience of a man who injured several barrels of tubers 

 severely by placing the generator directly underneath and only 

 a few inches below a large slat-work bin containing the potatoes 

 to be treated. Morse obtained similar results experimentally. 

 This led him to advise that " no potatoes should be placed directly 

 above the generator." In the same place he writes as follows con- 

 cerning the danger of injury: 8 " Five years of experience in treating 

 potatoes with formaldehyde gas generated in various ways indicate 

 that, if properly handled, the gas from 3 pints of 40 per ct. formal- 

 dehyde may be safely used to the 1000 cubic feet of space. In fact 

 over 3 quarts to the 1000 cubic feet have been used repeatedly with- 

 out injuring the germinating qualities of the tubers in the least." 



Two years later the same writer again published directions for 

 the gas treatment. 9 This time it was stated that " the disinfection 

 with formaldehyde gas should be done before the sprouts begin to 

 start on the seed tubers." The safety of the treatment, if made 

 according to directions, was reiterated. 



8 Vt. Sta. Rpt. 13:281; 14:232; 15:227; 16:166; 17:397; 18:287. 

 7 Morse, W. J. Potato diseases in 1907. Me. Sta. Bui. 149. 1907. 

 H Loc. dt. p. 314. 



,J Morse, W. J. Blackleg: a bacterial disease of the Irish potato. Me. Sta. Bui. 

 174. 1909. 



