42 



BULLETIN 102, U. S. DEPARTMENT OP AGRICULTURE. 



a limit which would be practical from the standpoint of commercial 

 grading. In the same sense that corn with an acidity of 20 c. c. is of 

 poorer quality than corn with an acidity of 15 c. c, an acidity of 27 

 c. c. denotes poorer quality and a further advance toward wholly 

 bad corn than an acidity of 25 c. c. 



In the commercial classifying of corn according to quality and 

 soundness by means of the acid test, this investigation would recom- 

 mend but one limit 

 between the limits of 

 22 and 30 c. c, and 

 that it be placed at 

 26 c. c. 



The results of this 

 investigation show 

 that corn with a de- 

 gree of acidity below 

 22 c. c. is normally 

 sound and of first- 

 class quality from 

 the commercial 

 standpoint; that 

 corn with a degree 

 of acidity between 

 22 and 26 c. c. is in- 

 ferior in quality and 

 soundness, due to de- 

 terioration of the 

 germ; that corn with 

 a degree of acidity 

 between 26 and 30 

 c. c. has deteriorated 

 sufficiently to be con- 

 sidered unsound; 

 and that corn with a 

 degree of acidity 

 greater than 30 c. c. 

 is badly damaged 

 and of a very low 

 quality. It must be 

 remembered in the application of the acid test that the sample as a 

 whole must be considered and not individual kernels. 



The question will perhaps arise in the minds of some why the 

 degree of acidity of corn was taken as the one important chemical 

 factor in establishing its condition or quality. The answer to this 

 question will be found in carefully studying Table XX, comparing 

 the change in the different factors throughout the experiment. This 





. 'mar apr mrjumjuiy aog stpr ocr hov"jan feb mar apr may 





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Fig. 31.— Curves comparing the monthly average degree of acidity 

 of sound corn with the monthly average degree of acidity of 

 damaged corn as determined by mechanical analyses of corn 

 arriving at a principal terminal market. 



