GENUS MARANTA. 819 



Polariscopic Properties. — The figure is usually eccentric, distinct, clear-cut, and irregular. 

 Its lines are usually well defined, comparatively narrow, and approaching the same size and dis- 

 tinctness throughout, with a tendency to widening at the margin. Usually four lines appear and 

 may be somewhat bent or otherwise distorted and placed at varying distance from one another, 

 and the longer lines may cross the grain diagonally, longitudinally, or transversely. 



The degree of polarization is high. It is higher if the grain is viewed on edge or end, and it 

 varies somewhat in different grains and in some grains in the same aspect of a given grain. Polari- 

 zation is about the same as in M. arundinacea, but the variations are greater. 



With selenite the quadrants are well defined, irregular in shape, and unequal in size. The 

 colors are generally pure. 



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

 violet, a little deeper than M. arundi?iacea; with 0.125 per cent solution they tint lightly at first 

 and the color deepens slowly, but more rapidly than in M. arundinacea. After heating the solu- 

 tion until the grains are completely gelatinized, the grains are deeply colored with iodine, but 

 the solution is colored lightly, if at all. After boiling for 2 minutes, the grain-residues color less 

 and the solution very markedly. On the addition of an excess of iodine the capsules are colored 

 violet, while the contents of the grain-residues representing the greater part of the grain are of an 

 indigo color. 



Staining Reactions. — ^With gentian violet the grains begin to stain slightly at once and after 30 

 minutes are fairly stained. The individual grains are evenly colored, but some grains more deeply 

 than others. The color is a little deeper than in M. arundinacea. 



With safranin the grains begin to tint at once and in 30 minutes are fairly deeply stained, 

 slightly deeper than in M. arundinacea. 



Temperature Reaction. — The temperature of gelatinization is 71° to 72° C, mean 71.5°. 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins at once. A few grains 

 are gelatinized in 45 seconds, nearly all in 2 minutes, all but a few resistant grains in 3}/2 minutes, 

 and all in 10 minutes. The hilum becomes very distinct as a small black spot or bubble. The 

 lamellae are rendered invisible. The distal end and the tips of the spicules and nipple-like processes, 

 whenever they appear, may become dark, and gelatinization begins at these parts with swelling and 

 protrusion, which is especially marked at the distal end. The process extends sometimes half way 

 around the margin. Occasionally swelling occm"s at both ends. Usually after a time the grains 

 swell out enormously at the distal end and sides, leaving a triangular portion, including the hilum, 

 that remains for a time ungelatinized; later this portion is also included in the process. The gelat- 

 inized grains are large, but do not exhibit much distortion of the original shape. They often show 

 alternate light and dark bands at the distal end and in the body of the grain. These bands may not 

 be entirely separated, and proximally there is a clear, smooth, round space representing the swollen 

 hilum. In some cases the interior of the grain is very dark and shows merely irregular fissures. 



The reaction with chromic acid begins in two-thirds of the grains in 15 seconds, is over in prac- 

 tically all in 2 minutes, and in all in 5J^ minutes. The hilum and sometimes the lamellse become 

 prominent. Two refractive lines now appear to extend from the hilum, one on each side, to the 

 distal end of the grain, outlining an oval, inner space, which becomes divided by fine, longitudinal 

 striae or fissures which extend from the hilum. The hilum now swells enormously and, as it 

 enlarges, the striated, inner portion of the grain is pushed before it towards the distal end. The 

 margin becomes distinct and much thicker at the distal than the proximal end, and shows fine or 

 coarse striations according as the grain reacts quickly or slowly. The marginal part of the grain is 

 in the form of a capsule and becomes dissolved at one point at the proximal end where it is thin, 

 and the inner part of the grain flows out and is dissolved, followed by solution of the remaining 

 part of the capsule. In a few cases a formation of crescents occurs as in certain other starches. 



Reaction with pyrogallic acid begins at once. Most of the grains are gelatinized in 30 seconds 

 and all in 65 to 105 seconds. After a bubble appears at the hilum, the hilum and lamellae become 

 very distinct. The hilum swells slightly, and at times refractive lines extend from each side to the 

 distal end and fine striaj radiate from the hilum through the grain. The hilum now swells greatly 

 and the bubble is moved to one side and then disappears. The inner part of the grain is pushed 

 by the swelling process towards the distal end, which becomes granular. The margin is broad 

 and very distinct, is finely striated, and shows two or three bands. This banded appearance 

 eventually clears away, as does also the granular mass at the distal end. The swollen grains so 



