GENUS ZINGIBER. 



781 



protrusion. In some grains one or two irregular points in the margin also swell. This process ex- 

 tends all around the margin and is characterized by great irregularities. It now extends inward 

 slowly, and sometimes the inner, ungelatinized portion is divided by fissures into separate pieces 

 which swell separately. The gelatinized grains so formed are very large, greatly distorted, folded, 

 crumpled, and sacculated. 



With Purdy's solution the reaction begins immediately and is over in IJ^ minutes. The hilum 

 and one or two contiguous points protrude, fine strise radiate from the hilum throughout the grain, 

 and the entire substance of the grain is changed gradually into a gelatinous mass. The gelatinized 

 grains are large, ovoid in shape, and often very smooth. Rarely, the two ends of the grahi begin to 

 react first, and then the central portion. 



STARCH OF ZINGIBER OFFICINALE VAR. JAMAICA No. 1. (Plate 80, figs. 479 and 480. Chart 325.) 



The starch was prepared from the ground white rhizomes bought in the open market and sold as 

 Jamaica ginger. 



Histological Characteristics. — In form the grains are usually simple. There are rare compound 

 grains consisting of two or three components; also a few aggregates and clumps, but no pressure 

 facets. The surface of the grains is smooth and there is not much irregularity of outline. The 

 margin may be marked by small, rounded protuberances, depressions, or nipple-like projections. 

 The most conspicuous forms are the short, broad, ovoid, and oval; also flattened ovoid and oval, 

 nearly circular, approaching the clam-shell type, sugar-loaf, rounded, triangular, and rounded 

 quadrilateral. There is a tendency to a nipple-like protrusion at the proximal end of many grains. 

 The grains are so much flattened that top and bottom sides are almost parallel, and the thickness 

 is about one-fourth of the breadth. There is more or less 

 amorphous foreign matter adherent to some gi-ains. 



The hilum is not distinct, but usually visible and 

 quite eccentric. It is a small, round spot with two non- 

 refractive lines or fissures which extend outward and 

 downward from it on the sides. Occasionally the hilum 

 shows a small transverse or a 3-armed fissure, not wide 

 or deep or prominent. There are apparently no double 

 hila. 



The lamella are fairly distinct, fine, regular, appar- 

 ently continuous segments of rings, not showing any 

 irregularities; rarely several may be more prominent 

 than the others. They were not distinct enough in any 

 grain to determine the number accurately. 



The grains vary in size from 5 to 45/i. The common 

 size is 30ju. 



Polariscopic Properties. — The^^wre is very eccentric, 

 distinct, but not clearly defined. Its lines are broad and 

 not sharply defined, and tend to become somewhat wider 

 and less sharply defined as the margin is approached. 



Two marginal lines are usually the only part of the figure seen; occasionally three or four lines are 

 observed. There may be bending and other irregularity of the figure, due to depressions or eleva- 

 tions on the surface of the grain and to the addition of later deposits of starch at the base of some 

 of the grains, which causes the appearance of a cross-bar connecting the two long lines about two- 

 thirds of the distance from the hilum to the margin. 



The degree of polarization is low, much lower than in Z. officinale. The distal end is apt to be 

 more polariscopic than other parts. Polarization varies with the position of the grain, being much 

 higher when the grain is viewed from the end or side. 



With selenite the quadrants are not clearly defined, fairly regular in shape, but unequal in size. 

 The colors are not pure, both yellow and blue appearing to be mixed with much red. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color a fairly deep blue-violet, 

 but less than Z. officinale; with 0.125 per cent solution the grains tint very lightly and the color 

 deepens slowly, but at no time does it become so deep jjs that of Z. officinale. After heating in water 

 until the grains are completely gelatinized, the solution is colored very lightly and the grains generally 



Curve of Reaction-Intensities of Starch of Zingiber 

 officinale var. Jamaica No. I. 



