ACIDITY IN DETERMINING SOUNDNESS OF CORN. 
41 
PSf? CSA/T OP TOTAL SAMPLES. 
20 30 0O SO 60 70 BO 
90 
The monthly average acidity of corn considered damaged and the 
monthly average acidity of corn considered sound, as separated from 
samples representing approximately 3,000 cars received at a terminal 
market, compare with the relation of the degree of acidity of corn to 
its general appearance. (Fig. 31.) It will be seen that the corn 
appearing sound to the eye was uniformly low in degree of acidity, 
exceeding the limit 
of 22 c. c. only 
slightly in any of the 
months. Attention 
is also called to the 
increase of acidity in 
both the sound and 
damaged corn 
through the summer 
months, until the ar- 
rival upon the mar- 
ket of the new crop. 
Of 127 samples of 
corn selected for 
seed,, only three 
showed a degree of 
acidity above 22 c. c, 
and these samples 
showed evidence of 
deteriorationthrough 
their low germina- 
tive power. (Fig. 
10.) 
With a knowledge 
of the fact that as 
corn deteriorates the 
degree of acidity in- 
creases and from the 
results of investiga- 
tions as described in 
the preceding para- 
graphs, it is believed that 22 c. c. most closely denotes the first stages 
in deterioration and that any corn showing a degree of acidity greater 
than 22 c. c. is, by comparison, of lower quality and lacking in nor- 
mal qualities of soundness which it at one time possessed. 
From the theoretical standpoint it is undoubtedly true that corn 
with a degree of acidity of 15 c. c. more closely approximates ideal 
quality and soundness than corn with an acidity of 20 c. c. It has 
been the aim, however, in fixing the initial limit at 22 c. c. to choose 
Fig. 30.— Curves showing the percentage or samples of corn in each 
commercial grade tested for degree of acidity which fell below 15, 
below 16. below 17 and so on up to and including 32 c. c, repre- 
senting approximately 2,500 cars received at a principal terminal 
market from December, 1911, to May, 1913. inclusive. 
