210 The Potato 



aldehyde, costing about 30 cents, should be diluted with 

 30 gallons of water. This can be used over and over 

 again for at least ten times without losing strength, but 

 the quantity will, of course, be diminished with each treat- 

 ment. The tubers should be soaked in it for two hours. 

 A longer time may injure the sprouting power of the tuber. 

 When corrosive sublimate is used, four ounces of the dry 

 })owder, costing about 50 cents, should be used to 30 

 gallons of water. The powder should first be dissolved 

 in a quart or two of warm water and then added to the 

 other^ It dissolves more slowly in cold water. The solu- 

 tion should not come in contact with metal, as it reacts 

 with it and loses strength. Neither should it be used 

 more than three times in treating potatoes unless renewed 

 with fresh solution, for it loses its strength rapidly with 

 use. Tubers should be soaked in it for at least one and 

 one-half hours, but never longer than five hours. Great 

 care should be taken in its use, for it is exceedingly poison- 

 ous. Treated tubers should never be used as food. 



Where one has large quantities of tubers to be disin- 

 fected at one time, the formaldehyde gas treatment may 

 be used. For this purpose the tubers should be placed in 

 crates or in shallow slatted bins so as to permit the free 

 movement of gas about them. The disinfecting room 

 should be made as air-tight as possible. Spread potas- 

 sium permanganate evenly over the bottom of a large 

 deep pan or bucket. Twenty-three ounces should be 

 used for each 1000 cubic feet of space within the room. 

 Pour over the permanganate three pints of 40 per cent 

 formaldehyde for each 1000 feet of space. Give the pan 

 a tilt, leave the room as quickly as possible, and close the 

 door tightly, leaving it closed for 24 hours or, at least, over 

 night. The door can then be opened and the room aired 



