784 



STARCHES OP ZINGIBERACEjE. 



The hilum is very distinct as a dark spot or bubble. A line of irregular fissures extends down the 

 middle of the grain from the hilum to the base, and as the grain swells the inner portion is converted 

 into a gelatinous, finely granular mass. Reaction occurs most rapidly at and near the distal end. 

 The gelatinized grains so formed are usually large, smooth, rounded, sometimes irregular, sacculated, 

 and wrinkled. Many retain some of the original form of the grain. 



With Purdy's solution there is some reaction in many grains within 15 minutes and after 3 

 hours most of the grains are swollen, but none completely gelatinized. The hilum is very distinct 

 and the lamellse may be made out. The hilum swells somewhat, and there is splitting and Assuring 

 of the grain and generally swelling. 



STARCH OF ZINGIBER OFFICINALE VAR. COCHIN. (Plate 81, figs. 481 and 482. Chart 327.) 



The starch was prepared from rhizomes deposited in the Materia Medica Museum of the 

 Medical School of the University of Pennsylvania. It is a very old specimen, having been in the 

 museum for probably 50 years or more. 



Histological Characteristics. — Inform the grains are usually simple, with a few compound grains, 

 many clumps, no aggregates, and no pressure facets. The surface is quite smooth and tends to be 

 quite regular. Nipple-Uke processes are common. The most conspicuous form is the flattened 

 ovoid, which often has a small, pointed projection at the proximal end; also oval, elliptical, circular, 

 and various irregular shapes, a few of which approach the clam-shell type. The grains are much 

 flattened, and are about one-third as thick as broad. On edge they appear as long, flattened, nar- 

 row ellipses. 



The hilum is rarely visible and it appears as a small, round, non-refractive spot situated very 

 eccentrically, almost at the edge. It shows in some grains two non-refractive lines which extend 

 outward and downward from it, one on each side, but it is not fissured. It is usually in the median 

 line and it may occasionally be double. 



The lamdlcB are very indistinct, and when seen they appear as fine, regular arcs of circles, prob- 

 ably continuous; the hilum is so eccentric that it is difficult to determine whether they are contin- 

 uous or not. There are probably very many on one grain, some more prominent than others. The pro- 

 jections and mammary processes from the surface of the 

 grains are included in the structure of the original grain. 



The grains vary in size from 5 to 40fi. The common 

 size is 28/x. 



Polariscopic Properties. — The figure is very eccen- 

 tric, fairly distinct, though its lines are rather broad and 

 margins dim. Only one or two lines are usually seen. 

 If one line, it is in or near the median line, but if there 

 are two they are placed marginally. Parts of other lines 

 may also be seen in some grains. 



The degree of polarization is low, lower than that 

 of Z. officinale and about the same as that of Z. officinale 

 var. Jamaica No. 2. There is not much difference in dif- 

 ferent grains. When the grains are viewed from the end 

 or edge it is high. 



With selenite the quadrants are not well defined, are 

 fairly regular in shape, and unequal in size. Usually but 

 two quadrants are visible, or one with parts of two. 



Iodine Reactions. — ^With 0.25 per cent Lugol's solu- 

 tion the grains react readily and become a fairly deep 

 blue-violet; with 0.125 per cent solution the grains color very lightly. The reaction is somewhat 

 deeper than in Z. officinale. After heating in water until the grains are completely gelatinized, 

 the solution is colored fairly well and the grain fairly deeply on the addition of iodine. Many of 

 the grains have a violet-colored wall. After boiling 2 minutes the solution is colored very deeply 

 and the grain-residues very lightly or not at all. When an excess of iodine is added the capsules 

 appear violet-colored. 



Staining Reactions. — With gentian violet the grains begin to stain in less than a minute and 

 after 30 minutes the stain is fairly deep, not quite so deep as that of the grains of Z. officinale. 



Chart No. 327. 



Curve of Reaction-Intensities of Starch of Zingiber 

 officinale var. Cochin. 



