282 AGRICULTURAL CHEMISTRY 



desired variety has been able to hold its own. Some- 

 times this change is rendered necessary by conditions 

 which are beyond the power of man to modify. As an 

 example, No. 10 of Professor Blount's wheats, known as 

 " Oregon Club," a white variety from Oregon, has been 

 deteriorating every year since it has been grown in Colo- 

 rado, whereas if the seed had been supplied every season 

 directly from Oregon, the quality would probably have 

 remained the same. In extension of this illustration the 

 fact may be mentioned that the annual renewal of the 

 seed from a desirable and favorable source often makes it 

 possible to raise cereals where otherwise climatic con- 

 ditions would render their cultivation impossible through 

 rapid reversion. This is particularly the case with 

 extremes in latitude, the effect of which is not founded 

 so much upon the composition of the crop as on the yield 

 and size of the grain." 



384. Storage of Wheat in Elevators. When new 

 wheat is stored in elevators, a fermentation change takes 

 place known as "sweating." This affects, to a slight 

 extent, the chemical composition and milling qualities of 

 the grain. When wheat is not fully matured or is damp, 

 the fermentation which takes place causes the tempera- 

 ture to rise to 140 or more and occasionally high enough 

 to cause spontaneous combustion. Thoroughly sound 

 wheat undergoes but little change in temperature even 

 when stored in large elevators where 120,000 bushels are 

 placed in one compartment. The changes which take 

 place during storage are brought about by the enzymes 

 or soluble ferments in the grain, and the organized fer- 



