so April. 191-^.] W/zi-a/ a//d its Cultivation. 



This discrepancy is accounted for by the evaporation that has taken place 

 in the process of niilling, during which process considerable heat is 

 developed. 



The percenl:age of moisture present in wheat varies within very vi^ide 

 r.mits, and it has even been known to fluctuate considerably from day to 

 day with variations in the humidity of the air. The amount of moisture 

 in the grain becomes a matter of considerable commercial importance in 

 the drier portions of ths Commonwealth, especially in parts of South 

 Australia where at harvest time the temperatures are very high and the 

 atmosphere exceedingly diy. Under such circumstances, the moisture 

 content of the ripe grain is very low. When such gram is .stored for a 

 considerable time, or shipped to a more humid climate, a considerable 

 gain in weight may result. For example, judging from the evidence 

 given to the South Australian Royal Commission on the Marketing of 

 Wheat, it would appear that .75 per cent, to 3.5 per cent, of the total 

 weight of wheat was gained by merely storing the Avheat at the local 

 railway station for six months. 



On the other hand, it is conceivable that transferred from a moister 

 district the grain may even lose in weight by storage, more especially if it 

 were stored in a district relatively drier than that in which it was produced. 



2. Fat. — It will be noted from the table that the flour contains a 

 m.uch smaller percentage of fat than either bran, pollard or the grain 

 itself. Small as this percentage is, however, it is probably much higher 

 than the amount found in commercial flour m.ade from the same variety 

 of wheat. This arises from the fact that, in the experim.ental mill with 

 which this sample was milled, it is rather difficult to get rid of the whole 

 of the germ and to keep it out of the flour. 



Fat, of course, occupies a high position as a food stuff, but the amount 

 present in flour is so .small as to make it of secondary importance. The 

 fat of wheat is not found uniformly distributed throughout the kernel, 

 but is almost wholly concentrated in the germ and in the bran. 



It is owing to the high fat-content of the germ that it is so necessary 

 to eliminate it from the flour in the process of milling. The germ not 

 only discolours the flour, but is also a positive source of danger to the 

 keeping quality of the product, inasmuch as the fat of the germ readily 

 develops rancidity and impairs the value of the flour. 



3. Carbo-hydrates. — The principal constituents of the carbo-hydrate 

 group are starch, dextr'n, and sugar, of which starch is by far the most 

 abundant. It forms from 65 to 70 per cent, of the wheat grain, and 

 the great bulk of the endosperm from which the flour is ultimately 

 derived. The amount of dextrin and sugar vary considerably in different 

 varieties of wheat, but generally speaking, the amount is very small. 

 In sound wheat and flour the sugar is usually cane sugar. The presence 

 of much maltose, however, is an indication of unsoundness. 



Cellulose, the substance which makes up the " skeleton " of vegetable 

 organisms, the "fibre" which holds the various parts of the plant to- 

 gether, belongs to this group, and is found in the kernel in three forms — 



(«) The wTodv fibre, or ligaified cellulose of the bran. 



{6; Th'^ Darenchymxtous cellulo-e formina; the partitions of the endosperm. 



(c) The delicate fabric forming the envelope of the starch colls. 



4. Jisli. — The composition of the ash or inorganic portion of the 

 grain, the residue left on igniting the crushed grain, is very interesting. 



