438 
Journal of Agricultural Research 
Vol. XXVIII, No. 5 
3. (a) Information upon the comparative toughness of the kernels of different 
varieties of corn was obtained at 5-day age intervals throughout the growing 
and maturing period by means of an instrument devised specifically for the 
purpose. This measured the toughness of the kernels by showing the amount 
of their resistance to puncture. The features of this instrument are described 
and illustrated in the text. 
(b) In general there is a relation between the resistance to puncture of the 
fresh corn and the toughness of the canned product made from it. Since the 
resistance to puncture increases with age, tests of this kind may be used to 
indicate in a general way the age of the corn which may facilitate the selection 
of the proper stage for canning. 
( c ) The variations in toughness among different corns of the same age were 
found to be relatively small, though in a few instances, as with Crosby, a distinct 
varietal difference in this character was observed. 
( d ) Factors other than toughness of the pericarp may affect the texture of the 
grain in the canned product as was shown in the case of the product from the 
two field varieties in which the kernels were found to be considerably harder 
than the puncture tests would lead one to expect. 
4. ^ (a) In all the varieties of sweet and field corn tested the moisture content 
of the kernels decreased continually during the growth and maturing periods. 
The rate of decrease varied considerably in different varieties, the rate being 
most rapid in Golden Bantam, Dreer’s Golden Giant and Country Gentleman, 
and slowest in the Evergreens, Mammoth Sugar and Old Colony. Of the field 
varieties Boone County White showed a much slower decrease in moisture than 
Reid’s Yellow Dent. The relative rates in the decreases in moisture in the dif¬ 
ferent varieties was found to correlate closely with the relative rates in maturing 
as shown by field observations and the character of the product canned at 
various stages. The moisture content is also closely correlated with the con¬ 
sistency of the canned product of the sweet varieties, both as regards different 
varieties and different stages of maturity. 
5. (a) The percentage of sugar in the kernels of green corn was found to 
change constantly during the development and ripening of the ear. The total 
sugar continued to increase up to 15 days from appearance of silks and then 
decreased rapidly throughout the maturing period. The reducing sugars were 
high at first and steadily decreased throughout the growth and maturing periods. 
In contrast to this the cane sugar increased rapidly at first to the 15-day stage 
and then slowly decreased as the corn approached maturity. The general 
order of these changes was practically the same for all varieties, the slowly 
maturing varieties decreasing in sugar content nearly as rapidly as those matur¬ 
ing more quickly. 
(b) * These changes in the percentage of sugars profoundly affect the sweetness . 
of the canned product, though the percentage of total sugar is not an exact 
measure of the sweetness. This is determined rather by the nature and concen¬ 
tration of the sugar. That the composition of the sugar itself is changing is 
manifest by the change in the ratio of reducing to nonreducing sugar. Also 
the moisture content is constantly changing in the corn so that the percentage 
of sugar is changed without necessarily changing the concentration. These 
influences are manifested in the quality of the products canned at the 15 and 20 
day stages. The percentage of total sugar in the corn at the 15-day stage is 
much higher than at the 20-day stage but the difference in the sweetness of 
the two products is not as great as the percentage of sugar would indicate. 
6. (a) The total polysaccharides were found to increase continuously through¬ 
out the development and ripening of the ear of corn. As the nature and con¬ 
centration of sugars were found to affect the sweetness of the canned product, in 
like manner the amount and nature of the different polysaccharides were found 
