212 Journal of Agricultural Research voi. xvin, no. 4 



in commercial cold storage. The results indicate that when moisture 

 remains condensed in drops on the fruit there may be a slight increase 

 in the development of scald, but apparently because of the more restricted 

 aeration of the apple tissue rather than from any harmful effect of the 

 water itself. Apples stored in air that was saturated with moisture but 

 constantly stirred have not developed scald, while similar apples in dry, 

 stagnant air have become badly scalded. Apples have been exposed to 

 outside air by throwing a cold-storage room open freely when the tempera- 

 ture would allow, and by rolling the barrels out of the storage room for 

 one or two days each week; but scald has been reduced rather than 

 increased by the treatment. (See p. 223.) Apples that have been picked 

 wet or have had water poured over them after they were in the barrel 

 have developed no more scald than others picked and packed when 

 they were dry. The writers havfe found no evidence that excessive 

 humidity plays any important part in the development of scald either 

 under experimental or commercial storage conditions. 



Oxygen. — The apple is a breathing organism, and under conditions 

 of restricted aeration the percentage of oxygen in the air surrounding the 

 fruit is reduced below normal. The question naturally arises as to whether 

 this change in air composition has any influence upon the development 

 of scald. To test this point, apples were stored in air which had the per- 

 centage of oxygen reduced from 21 to 6.9, and others in air which had 

 the percentage of oxygen increased to 31.5. The amount of scald 

 developed in each lot was compared with the amount on apples held in 

 air having the normal percentage of oxygen. The reduced oxygen supply 

 resulted in no increase in the amount of scald, and the increased oxygen 

 supply gave no significant decrease in scald. In other experiments. 

 Grimes apples were held in 100 per cent oxygen at 20° C. for four days 

 and then removed from the oxygen and placed in moist chambers in 

 normal air, part of the apples being then stored at 15° and part at 2.5°. 

 Other apples were exposed to the same temperatures but were not given 

 the preliminary oxygen treatment. Notes were taken at various times 

 on the amount of scald, but no difference of any kind developed between 

 the apples that had been first stored in oxygen and those that had not. 

 The results are strikingly different from those reported later from similar 

 experiments with carbon dioxid. (See p. 213.) The results of the various 

 experiments seemed to prove conclusively that the small variations in 

 the oxygen content that ordinarily occur in the storage air are not matters 

 of importance in determining the development of scald. 



Ozone. — Although an increased oxygen supply resulted in little 

 or no decrease in the amount of scald, it seemed possible that a more 

 powerful oxidizing agent might give different results. So in the fall 

 of 1 91 8 both laboratory and commercial cold-storage experiments were 

 made with ozone. 



