GENUS ZINGIBER. 



783 



The lamellce are not usually visible. When they can be seen they are very faint and appear 

 to be regular, fine arcs of circles, commonly quite uniform in size and distinctness. Rarely one or 

 two were coarser and more distinct than the others. They are so faint that it is impossible to count 

 them with any accuracy. 



The grains vary in size from 4 to 42/i. The common size is about 28/i. 



Polariscopic Properties. — ^The figure is distinct, but not clearly defined. Its lines are usually 

 thick and the edges are dim. The lines are not bent or otherwise distorted. 



The degree of polarization is low. It is lower in Z. officinale and Z. officinale v&t. Jamaica No. 1. 

 When the grains are viewed from the edge or from the end they appear highly polariscopic. 



With selenite the quadrants are not especially well defined, are unequal in size, regular in shape. 

 The colors are not pure. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color immediately a fairly 

 deep blue-violet, not so deep as Z. officinale and about the same as Z. officinale var. Jamaica No. 2; 

 with 0.125 per cent solution they tint lightly at once and the tint deepens slowly. After heating 

 in water until the grains are completely gelatinized, the solution is somewhat colored and the grains 

 fairly deeply by the addition of iodine. Some show a 

 violet capsule. After boiling for 2 minutes the grain- 

 residues are less deeply colored, but the solution much 

 more deeply. All the grains show a violet capsule, and 

 there are capsules which do not retain any blue-react- 

 ing starch. 



Staining Reactions. — With gentian violet the grains 

 begin to stain at once and after 30 minutes are all fairly 

 deep, some more than others. The coloration is lighter 

 than in Z. officinale. 



With safranin the grains begin to stain lightly in a 

 minute, but slowly, so that at the end of 30 minutes they 

 are only lightly stained. The color is less than that of 

 Z. officinale. 



Temperature Reaction. — The temperature of gelatin- 

 ization is 85.5° to 86.3° C, mean 85.9°. 



Effects of Various Reagents. — With chloral hydrate- 

 iodine the reaction begins in most grains in 45 seconds 

 and is complete in all in 8 minutes. The hilum is very 

 distinct as a dark bubble or spot. The lamellae are invis- 

 ible. The margin, as in most other starch-grains, becomes darker and clearer. Irregular points at 

 the distal end and sides of the grain now darken and protrude. The hilum at this time frequently 

 swells out into a small knob. From these points the process extends over the whole grain, smoothly 

 and without any more swelling at one point than at another. There is in the grains occasionally a 

 perpendicular fissure which extends from the swollen hilum almost to the distal end of the grains. 

 The grains are uniformly dark and show resemblance to the original form of the grain. 



The reaction with chromic add begins in 2 minutes and is over in 13 minutes. The hilum be- 

 comes very prominent, and the lamellae may be made out dimly. As the hilum swells slightly, fine 

 striae appear which radiate throughout the grain, growing coarse and more distinct. In the majority 

 of the grains the whole interior now changes into a gelatinous, finely granular mass inclosed in a thin 

 capsule, which dissolves at one point and opens out, thus allowing the gelatinized starch of the inside 

 to flow out and dissolve. The remaining portion of the capsule dissolves slowly. In a few grains 

 the hilum swells out quickly before other parts of the grain react in any way, and following its solu- 

 tion the rest of the grain disappears, the gelatinous starch flowing out of the opening at the hilum. 



Reaction with pyrogallic add begins in some grains in 3 minutes and about half the number 

 are partially gelatinized in 35 minutes. The hilum is prominent and some fine lamellae may be seen. 

 The hilum swells somewhat and fine striae app(\ir radiating throughout the grain. The entire grain 

 now appears to be transformed into a finely granular, gelatinous mass which gradually expands, 

 forming a large mass with a thin capsule. This capsule does not show many folds, lines, or wrinkles. 



The reaction with ferric chloride begins in a few grains in 3 minutes. It is general in about 15 

 minutes, when about one-fourth are completely gelatinized. The reaction is over in 45 minutes. 



85.9° 

 Curve of Reaction-Intensities of Starch of Zingiber 

 officinale var. Jamaica No. 2. 



