138 Journal of Agricultural Research voi. xvii, No. 4 



the experiment was begun. However, the data are interesting; they 

 show the usual low sugar content of green corn as it is now purchased 

 on the market. The percentage of sugar in this com ranged from 1.70 

 to 1.49. 



EXPERIMENTAL METHODS 



One of the first problems to solve was a method by which the rate of 

 the carbohydrate changes at different temperatures could be determined 

 without comparing analyses of different ears. The following method 

 was finally adopted: The ears for each experiment were brought to the 

 laboratory within 15 minutes after picking and numbered consecutively. 

 The first set of samples was taken from ears i and 2 , and all ears were then 

 placed immediately under the experimental conditions. At the end of 

 24 hours the second set of samples was taken from ears i and 2 and the 

 first set from ears 3 and 4. After 48 hours the second set of samples 

 was taken from ears 3 and 4 and the first set from ears 5 and 6. This 

 overlapping method of sampling was continued every 24 hours until the 

 experiment was completed. The change in chemical composition dur- 

 ing each consecutive 24-hour period of storage could then be determined 

 by comparing the analytical results of the first and second sets of samples 

 from the same ear. 



Stowell's Evergreen corn was stored at seven different temperatures — 

 namely, 0°, 5°, 10°, 15°, 20°, 30°, and 4o°C. All the temperatures were 

 controlled within about i °. The 30° temperature was controlled within 

 0.1°. The com was stored with the husks on, and, in the case of the 

 higher temperatures, the ears were placed in large desiccators, with the 

 tubulure on the side left open to allow ventilation. Preliminary experi- 

 ments showed that, as far as the carbohydrate changes are concerned, 

 active aeration of the small number of ears used in each experiment was 

 not important during the short experimental period of four days. 



Under the conditions of the experiments there was very little change 

 in the percentage of water in the corn at any temperature. However, 

 the analytical results from the second set of samples were all calculated 

 to the moisture of the first set in order to avoid false percentages due to 

 loss or gain in water content during storage. In a few cases at the higher 

 temperatures the percentage of water slightly increased on account of 

 the accumulation of respiratory water and possibly water set free by 

 condensation of polysaccharides. 



ANALYTICAL METHODS 

 SAMPLING 



Three rows of kernels were removed for each set of samples, care being 

 taken to remove the entire kernel. In order to take the first set of sam- 

 ples, the husks were split lengthwise with a sharp knife and then cut 



