36 



BULLETIN 102, IT. S. DEPARTMENT OP AGRICULTURE. 



RANGE IN PERCENT AGE Of DAMAGED KERNELS 



JTO *" 10 TO MORE THAN ^ 



' 'LESS than 

 (60 



\ 



JX- 



\ 



^X 



A-e, 



-Xz- — 



-va- 



cated by the acidity test, and the results of this investigation suggest 

 the acidity test as a method to be used in determining accurately the 

 soundness and quality of corn. 



Let us consider, for example, that a sample of seed corn showed 

 upon test a degree of acidity of 15 c. c. This represents approxi- 

 mately the acidity of 

 the average corn se- 

 lected for seed. Now, 

 let us consider that a 

 sample of corn con- 

 sisting entirely of cob- 

 rotten or otherwise 

 damaged kernels 

 showed upon test a 

 degree of acidity of 

 45 c. c. This repre- 

 sents the degree of 

 acidity of corn selected 

 by the Office of Gram 

 Standardization as be- 

 ing most typical of 

 damaged kernels 

 found in commercial 

 corn arriving at termi- 

 nal markets through- 

 out the country. Sup- 

 pose the two samples 

 be mixed in the pro- 

 portion of 90 per cent 

 seed corn and 10 per 

 cent damaged corn. 

 The degree of acidity 

 of this sample would 

 be theoretically 90 per 

 cent of 15 c. c. plus 

 10 per cent of 45 c. c, 

 or 1 8 c . c . This would 

 stamp the sample as 

 being commercially 

 sound corn. 



Let us consider fur- 

 ther a sample of average sound corn as determined by mechanical 

 separations of samples from several thousand cars of corn arriving 

 at terminal markets. The acidity of such corn is shown by this 

 investigation to be approximately 19.5 c. c. If a sample be 



JZPJSTURE 



Fig. 27.— Curves showing the relation of the degree of acidity 

 and the percentages of germination and moisture to the range 

 in percentage of damaged kernels as found in samples of corn 

 (average of all grades) arriving at a principal terminal market 

 (C) from December, 1911, to November, 1912, inclusive. 



