188 Report of the Department or Botany of the 



A PERPLEXING CASE OF INJURY. 



In the spring of 1912 the writers undertook, for the first time, the 

 disinfection of a quantity of seed potatoes in the manner recommended 

 by Morse. The room used was a cellar 31.4 x 13.3 x 8.4 feet with 

 a content of 3508 cubic feet. The floor and walls were of cement. 

 The ceiling was airtight and the two windows nearly so, but around 

 the door there was some opportunity for leakage of gas. At the time 

 of treatment the cellar contained 87 bushels of potatoes and four 

 bushels of apples. The potatoes were in slatted bushel crates piled 

 two and three deep and arranged so as to permit of the free circula- 

 tion of the gas about them on all sides except the top and bottom. 

 Three generators were used. Two were large tin dishpans and the 

 third a bushel measure of galvanized iron. They were placed on 

 the floor, at equal distances apart, through the center of the cellar. 



Each of the two dishpans was charged with 23 ounces of potassium 

 permanganate crystals and 3 pints of 40 per ct. formaldehyde 

 solution, while the bushel measure contained 35 ounces of potassium 

 permanganate and 4.5 pints of formaldehyde. The total weight of 

 permanganate was 81 ounces and the total quantity of formalde- 

 hyde 10.5 pints. Thus the chemicals were used in almost exactly 

 the quantity and proportions recommended by Morse. The crates 

 of potatoes were so disposed that none were nearer than 2.5 feet 

 to a generator and none farther away than about 8 feet. The floor 

 of the cellar was wet and the walls and ceiling damp with drops of 

 condensed moisture. The humidity is not known but it must have 

 been high. The temperature was about 45 degrees Fahr. The 

 generators were started and the door closed at 2:30 P. M., May 1. 

 Twenty-six hours later the door was opened and left open. At 8 :30 

 A. M. on May 3 (16 hours after opening the door) the gas was still 

 so strong in the back part of the cellar that one could not stay there 

 more than a few minutes at a time. Accordingly, the windows were 

 opened and a circulation of air secured. It must be that practically 

 all of the gas was removed within 48 hours of the time of starting 

 the generators. It appears that the dishpans were too small or too 

 shallow since some of the residue was found on the floor around 

 them after the cellar was opened. 



On May 7 the writers were much surprised to find that the treat- 

 ment had resulted in serious injury to some of the tubers, particularly 



