commerce in maize grain 595 



elevator warehouse, shows little tendency to heating except at CHAP 

 the time of year when germination usually takes place (which 

 in the Corn-belt is about the middle of June) and in September ; 

 and in South Africa about October and November. When 

 there is a tendency for the grain to sprout, special care should 

 be taken to keep it dry. " Winter-shelled corn keeps as long 

 as cold weather lasts, but when spring opens up it should 

 be sent to the consumer at once as it is almost sure to heat" 

 {Bowman and Crossley, I). 



552. Loss of J V eight and Damage Due to Heating. — "Grain 

 in a heated condition loses rapidly in weight. The Shippers 

 Manual for 1907, of the Chicago Board of Trade, reports a 

 single car-load of hot corn shrinking 3,600 lbs. The Chicago 

 Board of Trade has frequently weighed cars of hot corn on 

 railway truck scales, day after day, the loss of weight being 

 150 lbs. per day per car-load." According to Prof. L. G. 

 Michael, Chemist of the Iowa State Agricultural Experiment 

 Station, " heating occurs when grain originally in a moist con- 

 dition is put in bulk, thereby preventing it from drying out 

 and consequently subjecting it to the action of fermentative 

 bacteria or of plant growths resembling yeasts. All changes of 

 this kind generate heat, which in time raises the temperature to 

 such a degree that oxidation sets in. This may be so rapid as 

 to cause spontaneous combustion. The heating is due almost 

 entirely to fermentation which attacks the starch, changing it 

 first to sugar which produces alcohol, and later acetic acid. If 

 heating is continued for any length of time a decided loss of 

 starchy matter results from the conversion of the starch to 

 alcohol, with of course more or less injury to the unconverted 

 starch. The matter of damage through heating is one of 

 degree, from almost no harm, through slight rises in tempera- 

 ture, to almost complete ruin when fermentative changes are 

 allowed to reach any advanced stage." 



553. Degree of Dryness Required for Export. — If maize 

 contains more than a certain percentage of moisture when 

 shipped, it is apt to heat in the hold of the vessel, and to get 

 musty and "out of condition ". North American and Argen- 

 tine maize often arrives in Europe in a damaged condition on 

 this account, and some of the earlier shipments of South 

 African maize also caused complaint. 



38* 



