600 STARCH, SUGAR, GUM, AND CIL, IN WHEAT. 



cool, the flaky powder falls to the bottom, and may l-e collected, dried, 

 and weighed. If the water, after filtration, be CAaporated to dryness on 

 the water bath, a residue will be obtained, which consists chiefly of solu- 

 ble sugar, gum, and saline matter, with a little fatty matter, and sparingly 

 soluble caseine* (p. 117). 



3°. Gluiine arid oil. — \U further, the crude gluten be boiled in alco- 

 hol, a solution is obtained which, on cooling, deposits a w bite flocky sub- 

 stance, having much resemblance to caseine. When the clear solution is 

 concentrated by evaporation, water separates from it an adhesive mass, 

 which consists of a substance to which the name of giutine is given, 

 mixed with a little oil. By digesting the mixed mass in ether the oil is 

 dissolved out from the giutine, and may be obtained in a pure state by 

 evaporating the ethereal solution. This oil possesses the general pro- 

 perties of the fatty oils, or of butter. As it is partly washed out, how- 

 ever, along with the starch, the whole of the fatty matter of the flour is 

 best obtained by boiling it in a considerable quantity of ether. 



4°. Vegetable jihrine. — The crude gluten, after boiling in alcohol, has 

 much resemblance to the fibre of lean beef, and has therefore been named 

 vegetable fibrine. When burned, it leaves behind an ash, containing, 

 among other substances, the phosphates of lime and magnesia, which 

 are to be considered also as among the usual constituents of wheaten 

 flour, t 



Thus, fine wheaten flour, in addition to the water it contains, and to 

 the small quantity of bran which is ground up along with it, consists of 

 vegetable fibrine, albumen, caseine, giutine, starch, sugar, gum, oil or 

 fat, besides the saline substances, chiefly phosphates, which remain in 

 the form of ash, when the flour is burned. All these substances vary in 

 quantity in different samples of flour, — their relative proportions appear- 

 ing to depend upon a variety of circumstances as yet little understood. 

 In the various analyses of flour that have hitherto been published, little 

 attention has been paid to the per-centage of oil, of giutine, or of caseine, 

 which the specimens examined have severally contained. In general, 

 the weight of the crude gluten only has been estimated, without extract- 

 ing from it either the oil or the giutine. 



The following table exhibits the approximate composition of some 

 varieties of French and Odessa flour as determined many years ago by 

 VauquelinJ : — 



* This caseine begins to form a pellicle on the surface, when the liquid is concentrated by 

 evaporation, and though it is generally present only in a small proportion {X to 1 per cent.), 

 yet the comparative quantities present in two samples of flour may be judged of by the 

 abundance in which the pellicle is formed. 



t The saline and other inorganic matter of grain resides chiefly in the husk, as may be 

 seen by the relative quantities of ash left by the flour, bran, &c., of several samples of Eng- 

 lish and Foreign wheat as determined in my laboratory — 



wvTTrijn rnnwN ^^^ ^'^^'^ ^^^ CENT. BY DRY. 



WHERE GROWN. pj„g pj^^j. ^^^^^^^ ^h&X^s. BraD. 



1°. Sunderland Bridge, near ^ ,.04 ..^ tQ en 



Durham S 



2°. Kimblesworth, do 115 38 49 67 



30. Houghall, do 0-96 30 5-6 7-1 



40. Plavvsworth, do 093 27 5-5 76 



5°. Stettin: '... M 45 6-2 6-9 



6°. Odessa 11 49 66 SO 



I Dumas' Traile de Chimie, vi. p. 388. 



