New York Agricultural Experiment Station. 191 



partially darkened room and kept under observation for at least two 

 weeks. Unless otherwise stated all tubers were thoroughly dry at 

 time of starting the experiment and of approximately the same 

 temperature as the air of the room in which the experiment was 

 made. The potassium permanganate was in the form of slender 

 needle-shaped crystals. In all except the first three experiments 

 the formaldehyde solution was taken from the same bulk. An 

 analysis made by the Chemical Department of the Station showed 

 that it contained 37.1 per ct. of formaldehyde. 



SEVERAL FACTORS INVOLVED. 



Since the treatment was made strictly in accordance with the 

 directions given by Morse it was evident that the injury was due to 

 some factor not recognized and, probably, not encountered by him 

 in his long experience with the treatment. Hence, the first step 

 in the investigation was to determine in what respects the conditions 

 of our case were unusual. It was noted: (1) That the temperature 

 was low (45 degrees Fahr.) ; (2) that the relative humidity was very 

 high (probably near the dew point) ; (3) that the quantity of potatoes 

 treated was small in proportion to the space (1.5 lbs. per cubic 

 foot); and (4) that the severely injured tubers were of the variety 

 Sir Walter Raleigh while two bushels of another variety, Rural New 

 Yorker No. 2, were only slightly injured. 



Ultimately, it was discovered that the unknown chief factor was 

 the small quantity of potatoes while the high relative humidity and 

 sprouted condition of the tubers were important accessories. Besides 

 these three principal factors there are, also, some minor ones which 

 require consideration. The several factors entering into the problem 

 will be discussed in turn. 



quantity of potatoes. 



In our original trial of the treatment (the one which brought about 

 this investigation) the cellar contained about 1.5 lbs. of potatoes 

 per cubic foot. As has already been stated, many of the tubers 

 were severely injured. Our early experiments (Nos. 1-12) were 

 all made with very small quantities of potatoes — less than one-half 

 pound per cubic foot — and severe lenticel injury resulted in every 

 case notwithstanding the temperature and humidity varied con- 

 siderably in different experiments. It then occurred to us to try 

 a much larger quantity. In Experiment No. 13 the fumigation 



