280 



F A R M E R S' REGISTER. 



[No. 5 



ent quantity of sugar, though it renders it more 

 dilflriilt to preserve the roots. M. Biot seem? to 

 think that the large proportion of sugar might 

 likewise be partly accounted lor b\' the sumuier 

 haviag been dry and hot. There did not appear 

 to beany (lexfrine, for the white precipitate, per- 

 ft^cily sohible in water, and not coagulahle b}' 

 heat, did not atFect the planes of polarization at 

 all, and consefjuently this precipitate was neither 

 albumen, gum, nor dextrine. 



Dextrirse was procured by MM. Biot and Per- 

 soz from laundry starch (ernpois) by acids cold or 

 hot, strong or diluted, by potass, or by hot water, 

 any one oj' which will rupture the envelopes, and 

 set free the dextrine. Water alone, however, as 

 M. Raspail proved, and x\lM. Biot and Persoz 

 verified, will not completely rupture all the envel- 

 opes of fecula, or at least extract all the dextrine, 

 utdess the boiling is continued lor a long time 

 with considerable quantities of water; because the 

 unbroken globules of fecula are apt to be held to- 

 gether in clots by the gum-like matter disengaged 

 from the broken ones, and in this manner are part- 

 ly protected from the tljll influence of the heat. 



The dextrine thus obtained by any of the fore- 

 *roing agents is uniformly the same, being com- 

 pletely decomposable by heat, while it can be ana- 

 lyzed into water, hydrogen, and carbonic acid 

 gaS; but no nitrogen has been found in it. When 

 treated with yeast, it undergoes the vinous fer- 

 mentation, while acids change it into a saccharine 

 syrupy but when tried by the rotatory polariza- 

 tion of light, this syrup has a greater power in 

 turning the planes towards the right than the su- 

 gar of starch, in the proportion of ten to three. 



Varieties in the unburst globules. — Before the 

 application of heat or any otlier agent to rupture 

 the envelopes of the globules and set free the sol- 

 uble dextrine, the globules themselves afford in- 

 teresting objects of investigation, as will appear 

 from the following important statement of M. 

 Raspail. He tells us (Chiniie Organique, 134,) 

 that in the Paris market he seldom found any 

 wheat flour not to a certain extent mixed with po- 

 tato starch, by which mixture the fraudulent deal- 

 er gains as much as 25 per cent. The potato 

 starch has scarcely any effect on the appearance 

 of the flour, and it requires experience and skill 

 to detect it by the naked eye, unless the quantity 

 ef starch be considerable, when the crystalline 

 appearance of the flour gives room for suspicion. 

 The fraud, however, is readily detected by the 

 microscope, and M. Raspad says he could thus 

 discover the starch if it constituted only one per 

 Gent, of the flour. In examinmg suspected ^fiour, 

 it is always more easy to pronounce that it is adul- 

 terated than to tell in what the adulteration con- 

 sists. The dimension and form of the globules, 

 as given by Raspail, are the chief means by which 

 such examinations can be made, and we think 

 that no extensive dealer ought to neglect making 

 himself" thorouirhly acquainted with these. He 

 has only to furnish himself with acominon micros- 

 cope, and a micrometer or glass plate divided by 

 very minute lines like afoot-rule, and by laying a 

 grain or more of flour on the micrometer, and ex- 

 amining it with his microscope to see how ma- 

 ny lines it covers, he will be enabled at once to 

 tell the quality and kind of the flour in question. — 



Micrometers divided so as to measure the 

 part of an inch may be employed. 



,th 



Potato. — The globules containing dextrine in 

 this root acquire a larger size than any hitherto 

 examined, being usually of fiom the yttoIo^'^ '^ 

 the yn'Vn^'^ P^'"'^ o'' 'i" iuch, or even the ynnoTflll 

 part of an inch. When fresh, they exhibit on the 

 surface concentric wrinkles which disappear on 

 drying. The form of these globules, when large, 

 is oval; when small, more spherical, the former 

 beinfr slightly contracted, anu bluntly triangular. 



Wheat. — The largest globules rarely exceed 

 the YoTrn'h part of an inch, or about half the size 

 of the largest potato globules. They are of a 

 round or spherical shape, and are much smaller 

 when taken from half ripened wheat. 



Barley. — The globules of barley are similar in 

 appearance to those of wheat, but are much 

 smaller, rarely exceedmg the yo^o^oo^h part of an 

 inch. 



Oats. — The globules of oats are oval and 

 yellowish, being from the yn#TOo^'^ ^° 'he 

 i 18-100,0001 h of an mch in diameter. The innu- 

 merable minute hairs of this grain ijive the meal 

 a sort of cottony appearance to the naked eye. 



Rije. — These globules are about the 2-iOOOth 

 part of an inch in diameter, of a Hat Ibrm, some- 

 what sharp on the edge, and marked with a black 

 cross or three black rays forming a central star, 

 which gives a black color to rye flour. 



Arrow-Root. — The genuine arrow-root from 

 Brazil may be dislintruished from the starch of 

 potatoes by boiling, which only produces in ar- 

 row-root an enlargement of the globules to four 

 times their original diameter, because, as M. Ras- 

 pail thinks, they are exposed to heat in the origi- 

 nal Brazilian preparation, while the globules of 

 the potato expand to twenty or thirty times their 

 original diameter. The largest globules of gen- 

 uine arrow-root do not exceed 16-10,000lh part of 

 an inch, and, like those of rye, exhibit through 

 their translucid surface black lines like a star, or 

 sometimes like the letter T. Potato starch is bel- 

 ter than the genuine arrow-root. 



Buckwheat. — The globules are yellow, and sel- 

 dom appearsolargeasthe4-10,000lh partofan inch. 



Maize. — Few of the globules at tain the size of the 

 98- -00,000th part of an inch. The dried fi?cula is 

 usually injured by grinding, being folded, wrinkled 

 and more or less rounded. When taken from the 

 half-ripe milky grain, they are suiooth, entire, 

 and quite round. Hence the dextrine of maize 

 is obtained in greater proportion fi-om the half^ 

 ripe seeds; and hence also the small proportion of 

 starch found by the usual modes of chemical ana- 

 lysis, though it actually exist in the grain. 



Peas. — The globules of peas are of the same 

 form as those of the potato, with an unequal sur- 

 face, and the largest are about the 2-lOOOih part 

 of an rich. 



Beans. — The globules are of the same size as 

 those of peas, but difler from being egg-oblong, 

 or kidney-shaped, sometimes appearing as if a 

 smaller grain were enclosed in the interior. 



Other globules were examined and measured 

 by M. Raspail, but these are the most ir'teresling 

 for our present purpose, and, before proceeding 

 farther, it is indispensable to impress upon the at- 

 tention of the reader, 



1st, That the globules constituting meal, flour, 

 and starch, whether contained in grain or roots, 

 are incapable of affording any nourishment as 

 animal food till they are broken. 



