New York Agricultural Experiment Station. 195 



56 degrees Fahr. and the maximum 62 degrees Fahr. When the 

 box was opened it was found that most of the gas had disappeared 

 though there was still left enough to cause the eyes and throat to 

 smart when one's head was held in the box. Apparently, there was 

 a little more gas than in Experiment No. 13. Not a trace of injury 

 of any kind appeared on the test tubers. 



Between Experiments 38 and 39 the door of the fumigation chamber 

 was left open for 2\ hours, but the stones were not removed. In 

 the second stone experiment (No. 39) the initial humidity was 

 68 per ct. and the maximum 90 per ct.; the initial temperature, 

 59 degrees, the maximum 62 degrees. There were 20 test tubers, 

 10 of which had barely started to sprout while the other 10 had 

 sprouts one-fourth inch long. The quantity of gas present when 

 the door was opened seemed to be about the same as in the previous 

 experiment. The only indication of injury was a slight browning 

 of the tips and bases of some of the larger sprouts. 



Between Experiments 39 and 40 the door of the fumigation 

 chamber was left open 67 minutes for airing, but the stones were 

 not removed. 22 In the third stone experiment (No. 40) the 20 

 test tubers bore sprouts one-fourth to one-half inch long. The initial 

 humidity was 63 per ct. and the maximum 88 per ct.; the initial 

 temperature 58 degrees and the maximum 61 degrees. The gas 

 present at the close of the experiment appeared about the same as 

 in the previous two experiments. Several of the larger sprouts 

 were browned a little at the base and a few were killed, but the eyes 

 sprouted again and the germination appeared normal. There was 

 no lenticel injury. 



These experiments with stones show the importance of adsorption 

 in formaldehyde disinfection. It appears that stones have practically 

 the same effect as potatoes in taking up the gas and preventing injury. 

 As chemical union between the formaldehyde and the stones is 

 impossible it must be that the gas was adsorbed on the surface of 

 the stones. Hence, we conclude that when potatoes take up formal- 

 dehyde gas it is chiefly by adsorption. 



That partly filling the fumigation chamber with stones or potatoes 

 should have the effect of preventing injury to the test tubers appears 



22 Even though the stones were aired somewhat between experiments their capacity 

 for adsorption must have been considerably reduced by the previous treatments. 

 However, it was not shown in the effects on the test tubers. 



