ACIDITY IN DETERMINING SOUNDNESS OF CORN. 
37 
made consisting of 90 per cent of this sound corn and 10 per 
cent of the damaged corn showing an acidity of 45 c. c, the sample so 
prepared would show theoretically a degree of acidity of 22.05 (90 
per cent of 19.5 c. c. plus 10 per cent of 45 c. c). This sample would 
be stamped as being "unsound corn" according to the acid test. The 
percentage of damaged kernels may vary considerably in corn 
regarded as sound by 
the acid test. This is 
dependent upon the 
degree of soundness or 
quality of the kernels 
judged by the eye as 
being not damaged. 
As a result of this 
GRADE 
M4 
S^ 
46 
44 
42 
40 
38 
36 
. 
X 
v \ 
N 
\ 
\ 
x ^ 
32 
30 
28 
26 
24 
22 
20 
18 
16 
14 
12 
IO 
e 
6 
4 
"^ 
i 
1 
1 
\ 
\ 
\ 
^ — "/ 
\ 
\ 
^^ J 
<1^< 
\ 1 
0^ 
\ 1 
S / 
An 
/ \ 
/ 
/ 
/ 
/ 
^ 
' 
,^" ' 
investigation, 22 c. c. 
is recommended as ap- 
proximately express- 
ing the maximum de- 
gree of acidity found 
to be contained in corn 
considered commer- 
cially sound. Corn 
showing a degree of 
acidity exceeding 22 
c. c. indicates the de- 
velopment of excessive 
acidity through the de- 
terioration of the germ, 
and is discriminated 
against as being of 
poorer quality than 
corn showing a degree 
of acidity less than 
22 c. c. 
In the determination 
of soundness and qual- 
ity of corn by means of 
the acid test, it is the 
large bulk of the corn 
which must bo consid- 
ered rather than the 10 or 15 per cent of damaged kernels which the 
sample under analysis may contain. The acid test measures defi- 
nitely the quality and soundness of the 85 or 90 per cent of the so- 
called "sound kernels) 1 ' as recognized by the analyst or inspector in 
his determination of 10 or 15 per cent of damaged kernels by means 
Fig 
Curves showing the increase in the degree of acidity of 
samples of corn from the high to the low grades where there is also 
a corresponding increase in percentage of damaged kernels and 
decrease in percentage of germination, as found to represent ap- 
proximately 900 cars of corn received at a principal terminal 
market (C) throughout a year, all of which corn contained less 
than 16 per cent of moisture and was graded according to quality 
and amount of damage. 
