2l6 



Journal of Agricultural Research voi. xviii, No. 4 



Table II. — Effect of various volatile substances on Yellow Newtown and Rome Beauty 



app les — Cont inued 



Substances used. 



Efiects. 



Alcohol 80 per cent, ethyl 

 acetate 20 per cent. 



Alcohol 90 per cent, ethyl 

 acetate 10 per cent. 



Alcohol 80 per cent, amyl 

 acetate 20 per cent. 



Alcohol 90 per cent, amyl 

 acetate 10 per cent. 



Ethyl malate 10 per cent. 



Ethyl butyrate. 



After 3 days' exposure to the vapors, Rome Beauty 

 apples had a brovvn, cooked appearance, the red 

 portions of the apples, however, being much less 

 affected than the green portions. 



After 7 days, Rome Beauty and Yellow Newtown ap- 

 ples had the appearance of being typically scalded. 

 The scalded areas occurred only on the green side 

 of the fruit and shaded off in severity as the blush 

 areas were approached. After standing in a warm 

 room for 4 days the browning had spread into the 

 flesh of the apple rather more rapidly than is 

 usual with scald, but aside from this the diseased 

 condition was typical of apple-scald. 



Only Rome Beauty apples were tested. The results 

 were practically the same as with 10 per cent 

 ethyl acetate, a quite typical scald being produced. 



Experiments were made with both Rome Beauty and 

 Yellow Newtown apples. The former were remov- 

 ed at the end of 3 days and the latter at the end of 7 

 days. The results were similar to those reported 

 for 10 per cent ethyl acetate, but the apples were 

 even more typically scalded. The browned areas 

 coincided in the most exact manner with the skin 

 areas natiurally susceptible to scald. 



Only about 10 cc. of the liquid were used, and the 

 apples were placed in a smaller jar than those men- 

 tioned above. No scald or other injury had been 

 produced at the end of 3 weeks. 



Experiments somewhat similar to those described 

 above gave results very much like those obtained 

 with ethyl acetate and amyl acetate. 



The results reported in Table II show that it is possible to produce an 

 apparently typical apple-scald within a few days by exposing the fruit 

 to the vapors of certain dilute esters. The fact that the disease can be 

 thus produced artificially when connected with the additional fact that 

 the apples themselves are known to give off esters or related gases makes 

 it seem probable that these substances play an important part in the 

 development of scald as it occurs in commercial storage. 



GAS ABSORBENTS AS SCALD PREVENTIVES 



In an earlier paper (5) experiments were reported showing that scald 

 can be practically prevented by wrapping the apples in paper that has 

 been infiltrated with fat or oil. Other experiments are reported later in 

 the present paper (see p. 233) that give full confirmation of these results 

 and also make it clear that the beneficial effects of the wrappers are not 

 due to modifications in the moisture or the carbon-dioxid content of the 

 air surrounding the apple. It is well known that fats and oils have a 

 great absorbing power for esters and other odorous gases, and because of 

 this property they are used commercially in the extraction of perfumery. 

 Cow butter takes up odors so readily that it is usually rendered unpal- 



