GENUS MARANTA. 823 



The degree of polarization is high. The average is about the same as in M. arundinacea. There 

 is a greater variation among the grains; in some it is lower, yet it is high in a larger proportion of 

 grains than in ^f. arundinacea. A variation in the same aspect of a given grain is much more fre- 

 quently observed than in those of M. arundinacea. 



With selenite the quadrants are clearly defined and clean-cut, about the same as in M. arun- 

 dinacea. They are commonly slightly imequal in size and irregular in shape, but less so than in 

 M. arundinacea. The colors are generally pure, the degree of purity being a little less than in M. 

 arundinacea. 



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

 violet, some a reddish-violet, which deepens rather rapidly, more quickly than in M. arundinacea; 

 with 0.125 per cent solution they soon color a rather light blue-violet, a little deeper Init some- 

 what redder than in M. arundinacea, which deepens rather rapidly. After heating in water until 

 the grains are gelatinized and then adding iodine, the solution becomes a deep indigo-blue, and the 

 gelatinized grains a dull, rather deep blue, some with a reddish tint to reddish-violet. The solution 

 is deeper and the grains rather lighter in color than in M. arundinacea. If the gelatinized grains are 

 boiled for 2 minutes and then treated with iodine, the solution becomes a ver}' deep blue, while 

 the grain-residues either do not color or become a very light blue, some with reddish tint, much 

 lighter than in M. arundinacea. With an excess of iodine the capsules color a deep old-rose to wine- 

 red, deeper and redder than in M. arundinacea. 



Staining Reactions. With gentian violet the grains begin to color lightly at once and in 30 

 minutes are lightly colored, lighter than in M. arundinacea. 



With safranin the grains begin to color slightly at once and in 30 minutes are fairly colored, 

 lighter than in M. arundinacea. 



Temperature Reactions. The temperature of gelatinization is 68 to 70 C, mean 69. This 

 temperature refers to the separated and round grains, since the rare, scattered grains which appar- 

 ently bear a resemblance to M. arundinacea are either entirely or partially gelatinized before sub- 

 jecting to heat. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins immediately. A 

 few grains are gelatinized in a minute, about half in 2 minutes, nearly all in 4 minutes, and all but 

 a few resistant gi-ains in 7 minutes, in which latter the reaction is usually complete in 10 minutes, 

 rarely in 15 minutes. The grains color an old-rose at once, which deepens in many to a wine-red 

 before the appearance of the bluish color which accompanies gelatinization. The hilum becomes 

 very distinct either as a dark dot, a ring, or a lustrous structure. Gelatinization starts at the distal 

 end of the dome-shaped grains, accompanied by a narrow line of bluish color which spreads quickly 

 to the sides and proximal end, and then advances more rapidly towards the hilum from these latter 

 points than from the distal end until the entire grain is gelatinized. In the round forms, which are 

 the most resistant of all the grains, gelatinization begins at indifferent parts of the margin, accom- 

 panied by a narrow border of bluish color that closes in around the structure at the hilum, which is 

 frequently large and metallic in appearance. The hilum gradually shrinks and becomes dark as 

 gelatinization approaches it, usually more rapidlj^ from one pole than the other, until the entire 

 grain is gelatinized and deeply colored. The gelatinized grains are uniformly swollen, are slightly 

 larger, and retain the general shape of the untreated grain. The reaction is qualitatively the same 

 as in M. arundinacea, but the structure at the hilum is more prominent and the grains color a pm-er 

 old-rose and more often become wine-red previous to gelatinization. 



Reaction with chromic acid begins immediately. A few grains are dissolved in 30 seconds, 

 nearly all in 2 minutes, all but parts of resistant grains in 3 minutes, and all in 3]-^ minutes. The 

 reaction is qualitatively the same as in M. arundinacea, except that the capsule more often either 

 breaks at both corners of the distal margin of dome-shaped grains, followed by the solution of the 

 sides and proximal end; or first ruptures at the proximal end, the lamella; and capsule of the distal 

 margin in each case being the last to undergo solution. In very resistant grains the solution of the 

 entire grain is very uniform, and occasionally the capsule at the distal margin is the fii'st part to be 

 ruptured. 



Reaction begins immediately with pyrogallic acid. A few of the grains are gelatinized in 10 



seconds, nearly all in 30 seconds, all but rare resistant grains in 45 seconds, and all in 60 seconds. 



The reaction is qualitatively the same as in M. arundinacea, but as the shapes of the grains are so 



different, the arrangement of the fissures is not the same, one extending from each end of the hilum 



54 



