SPICES AND CONDIMENTS. 159 



more prominent in the starch as obtained from a freshly cut surface. 

 The rings are more distinct, too, near the hilurn or nucleus, which in this, 

 as in all tuberous starches, is eccentric, shading off toward the broader 

 or more expanded portion of the granule. The hilurn appears as a 

 shadowy depression (Fig. 57) and with polarized light its position is well 

 marked by the junction of the arms of the cross, and it will be found by 

 comparison of Figs. 31 and 32, on Plate XYI, that in the potato it is 

 oftener at the smaller end of the granule and in the arrowroot at the 

 larger. With polarized light and a selenite plate the beautiful play of 

 colors is obtained which is the basis of Blyth's classification. The 

 smaller granules, which are nearly round, may readily be confused with 

 other starches, but their presence serves at once to distinguish this from 

 Maranta or Bermuda arrowroot starch. 



Karely compound granules are found composed of two or three sin- 

 gle ones each with its own nuclus. 



Of the same type as the potato starch are the various arrowroots, 

 the only one of which commonly met with in this country being the 

 Bermuda, the starch of the rhizome of Maranta arundinacea, and the 

 starch of Turmeric. 



Maranta starch. The granules are usually not so varied in size or 

 shape as those of the potato, as may be seen in Figs. 30, 31, and 32, 

 averaging about ,07 mra in length. They are about the same size as the 

 average of the latter, but are never found as large or as small, which, 

 together with the fact that the end at which the nucleus appears is 

 broader in the Maranta and more pointed in the potato, enables one to 

 distinguish the starches without difficulty. With polarized light the 

 results are similar to those seen with potato starch, and this is a ready 

 means of distinguishing the two varieties, by displaying in a striking 

 way the form of the granule and position of the hilum, as is illustrated 

 in Figs. 31 and 32. 



Curcuma or turmeric starch. Tumeric contains a starch (Fig. 63, 

 Plate XXVIII), which, although of the arrowroot class, is quite distinct 

 in appearance from those which we have described. It is most irregular 

 in outline, so that it is impossible to define its shape or to do more than 

 refer to the illustration. Many of the granules are long and narrow and 

 drawn out to quite a point. The rings are distinct in the larger ones. 

 The size is about that of the Maranta. 



Ginger starch (Figs. 41 and 42, Plate XXI, and Fig. 58, Plate XXVII). 

 This starch is of the same class as those from the potato and Maranta 

 and several others which are of under-ground origin. In outline it is not 

 oval like those named, but more rectangular, having more obtuse angles 

 in the larger granules and being cylindrical or circular in outline in the 

 smaller. 



It averages nearly the same size as Maranta starch, but is much more 

 variable both in size and form. The rings are scarcely visible even with 

 the most favorable illumination. 



