208 Report of the Department of Botany of the 



perature of the potassium permanganate was, in most cases, a little 

 above the initial temperature of the disinfection chamber. Only 

 in two experiments (Nos. 1 and 15) were there any indications 

 that the reaction had not been complete, and in these cases the low 

 temperature of the formaldehyde solution was probably responsible. 



For the purpose of securing information on this point the following 

 experiments were made: 



Experiment No. 1. In a large room in which the temperature of 

 the air was 35 degrees Fahr. two generators were started simul- 

 taneously. In one of the generators the temperature of the chemicals 

 at time of mixing was 51 degrees Fahr., in the other, 70 degrees Fahr. 

 In each case 30 cubic centimeters of formaldehyde solution were 

 poured upon 14.25 grams of needle-shaped crystals of potassium 

 permanganate. Although the reaction began earlier and was finished 

 earlier with the warm chemicals the end results appear to have 

 been practically the same, except, possibly, the residue from the 

 warm chemicals was a trifle drier than that from the cool chemicals. 

 For practical purposes both reactions were satisfactory. 



Experiment No. 2. Thirty cubic centimeters of formaldehyde 

 solution and 14.25 grams of potassium permanganate crystals were 

 exposed in the open air until they had acquired its temperature, 

 viz., 34 degrees Fahr. They were then mixed in a pint tin cup 

 having the same temperature. The mixture effervesced very feebly, 

 barely ruffling the surface, and the reaction was a complete failure. 



From these experiments it appears that the success of the reaction 

 depends upon the temperature of the chemicals rather than upon 

 the temperature of the air in the disinfection chamber. Whatever 

 the temperature of the room, good results may be expected when- 

 ever the temperature of the chemicals at time of mixing is above 

 60 degrees Fahr. 



sprouting. 



In our first three experiments conducted with sprouted tubers 

 during May, 1912, there was much eye injury as well as lenticel 

 spotting exactly as had occurred in the original case of injury. When 

 we began experimenting again in February, 1913, using unsprouted 

 tubers, there was much lenticel spotting but no eye injury. (See 

 Experiments 4, 5, 6, 7, 8, 10, 11, 12 and 13.) By using sprouted 

 and unsprouted tubers in the same experiment it was shown that 



