SPICES AND CONDIMENTS. 161 



angles. They form very brilliant objects with polarized light, but with 

 ordinary illumination show but the faintest sign of rings, and a well-de- 

 veloped hilurn, at times star-shaped, and at others more like a circular 

 depression. 



Rice starch (Figs. 35 and 36, Plate XVIII, and Fig. 55, Plate XXYI) 

 is very similar to corn starch, and easily confused with it, being about 

 the same size. It is, however, distinguished from it by its polygonal 

 form, and its well-defined angles. The hilum is more prominent and 

 more often stellate or linear. Several granules are at times united. 



Wheat starch (Fig. 34, Plate XVII, and Fig. 50, Plate XXVI) is quite 

 variable in size, varying from .05 to .012 mm in diameter. It belongs to 

 the same class as barley and rye, the hilum being invisible and the 

 rings not prominent. The granules are circular disks in form, and 

 there are now and then contorted depressions resembling those in pea 

 starch. It is the least regular of the three starches named and does 

 not polarize actively. 



Barley starch (Fig. 37, Plate XIX, and Fig. 51, Plate XXVI) is quite 

 similar to that of wheat, but does not vary so much in size, averaging 

 ,05 mm 5 has rings which are much more distinct, and very small granules 

 adhering to the largest in bud-like forms. 



Rye starch (Fig. 52, Plate XXVI) is more variable in size, many of the 

 granules not exceeding .02 uim , while the largest reach .06 to .07 mra . It 

 lacks distinctive characteristics entirely, and is the most simple in form 

 of all the starches we have described. 



Oat starch (Fig. 38, Plate XIX, and Fig. 53, Plate XXVI) is unique, 

 being composed of large compound masses of polyhedral granules from 

 .12 to .02 mm in length, the single granules averaging .02 to .015 mm. It 

 does not polarize actively as may be seen in figure and plate, and dis- 

 plays neither rings nor hilum. The illustration shows its nature with 

 accuracy. 



Our descriptions, it will be seen, do not agree entirely with those, of 

 other authors, which in the same way do not agree among themselves. 



This shows a variation in the peculiarities of size, shape, &c., which 

 must be carefully allowed for, and the necessity for every investigator 

 to compare a starch which he is desirous of identifying with authentic 

 specimens. 



STBUCTUEE AND PECULIARITIES OF THE COMMONER ADULTERANTS. 



Before proceeding to the consideration of the normal structure and 

 composition of the spices and condiments and the adulterations detected 

 in commercial specimens, it is well to become familiar with the charac- 

 teristics of the common adulterants and materials which are liable to 

 be used for this purpose. 



The starches have been already described and their value as a means 

 of identifying different vegetable materials noted. By this means we are 

 able to detect the different cereals which are often added as diluents. 

 22S23 Bull. 13, pt, 2 3 



