the; prevention of potato scab. 89 



Either solution can be used repeatedly, fresh being added as 

 fast as it is used up. Mr. Agee recommends, as a time saver, 

 the use of barrels with a spigot at the bottom and placed on 

 boxes. The barrels are filled with potatoes and the solution 

 poured over. When the time of disinfection is passed the solu- 

 tion is drawn off and poured into other barrels, already filled, 

 and the treated potatoes dumped out on the ground to dry. This 

 should be done on a clean grass sod and not on plowed land or in 

 any other place where the treated seed will be exposed to rein- 

 fection. 



II. Exposure of dry seed to formaldehyde gas. Applicable 

 where large quantities, up to car load lots are to be 

 treated at one time. 



Place seed tubers 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 3 

 pints of formalin. Close room at once and do not 

 open for 24 to 48 hours. (See details of method 

 described below.) 

 During the last decade formalehyde gas has, on account of 

 its merits, become the leading disinfectant for use in rooms fol- 

 lowing contagious diseases. The most common way of gener- 

 ating the gas has been to place the liquid in a dish over an oil 

 stove or other fire, lasting sufficient time to vaporize the entire 

 amount of liquid formalin used, then close the room tightly and 

 leave till the period of disinfection was over. The Vermont 

 experiment station has been trying this method with consider- 

 able success in the disinfection of scabby potatoes. The writer 

 has had the immediate oversight of the details of these trials 

 for the past 5 years and is satisfied that the results from this 

 •process are fully equal to those obtained by soaking, either in 

 corrosive sublimate or formalin solutions. Certain difficulties 

 were experienced with the process, the chief of which was the 

 element of danger from leaving the fire in the disinfecting room 

 for some hours without attention and the comparatively slow 

 evolution of the formaldehyde gas. In 1905 our attention was 

 called to the potassium permanganate method of generating the 



