396 STARCHES OF LEGXntflNOS^, 



figure which appears as a thick line, bisected at the ends and located in the longitudinal axis. The 

 lines are generally broad, irregular, and not clear-cut. 



The degree of polarization is fair to high, in most grains fairly high. It does not vary much in 

 different aspects of the same grain, but sometimes varies in the same aspect of a grain. Some- 

 times only very small portions of the grain are observed. 



With selenite the quadrants are, as a rule, not well defined, irregular in shape, and unequal in 

 size. The colors are pure to fairly pure. 



Iodine Reactions. — ^With 0.25 per cent Lugol's solution most grains color a rather light violet; 

 with 0.125 per cent solution they color a very light-violet. After heating in water until the grains 

 are completely gelatinized, the solution colors a deep blue and the gelatinized grains a fairly deep 

 blue on the addition of iodine. After boiling for 2 minutes, the solution colors very deeply and the 

 grain-residues rather lightlj'. The capsules all color violet when an excess of iodine is added. 



Staining Reactions. — ^With gentian violet and with safranin when viewed in masses, the grains 

 appear slightly stained at once and after remaining in the solution for 30 minutes they are lightly 

 colored. 



Temperature Reaction. — The temperature of gelatinization is 68° to 69° C, mean 68.5°. 



Effects of Various Reagents. — With chloral hydrate-iodine the reaction begins in a few grains 

 in a minute, gelatinization is complete in a small number in 3 minutes, about one-fifth are gelatin- 

 ized in 5 minutes, and about one-half in 30 minutes. After an hour very little further gelatinization 

 is noted, but the grains that are not gelatinized have become a golden-brown color and are finely 

 granular, the center being lighter in color and less granular, while the entire grain appears to be 

 surrounded by a clear capsule. The grains that are soon affected take on a very light violet color, 

 and the lamellae and the hilum become more distinct. Gelatinization frequently begins by the dark- 

 ening of one end of the grain, which spreads over the entire grain accompanied by uniform swelling. 

 The formation of protuberances during this reaction, which is observed in grains of so many other 

 sources, is absent. In the bean-shaped grains gelatinization often starts at the depression located about 

 the middle of one side of the grain and proceeds slowly both forward and laterally, a clear, irregular 

 line being pushed ahead of the advancing gelatinization. Occasionally one or more strands of color 

 extend from the deeply stained, gelatinized mass through the grain. In round forms, a ring of 

 more deeply stained substance appears around a light, unstained central mass and slowly advances 

 over the grain. 



Reaction with chromic acid begins immediately. A few grains are gelatinized and dissolved 

 in 25 seconds and all in 10 minutes. The lamellae become very distinct, the refractive and non- 

 refractive lamelliE being sharply defined, and fine striae appear on the refractive lamellae. One or 

 more branched clefts are formed in the central non-lamellated area, and fine fissures penetrate 

 every part of the grain, which now swells uniformly and assumes an oval shape, gradually becoming 

 very clear and then collapsing suddenly. A round grain with a distinct hilum is occasionally ob- 

 served, in which the hilum as well as the lamellie become distinct, followed by the process already 

 noted. A few refractive granules are sometimes formed during the reaction. These are dissolved 

 with the rest of the grain. 



The reaction with pyrogalUc acid begins in a few grains immediately. It is complete in some 

 in a minute, in the majority in 3 minutes, and in all in 5 minutes. The hilum in the round forms 

 swells and becomes more distinct. In the elongated forms the hilum is not observed, but there are 

 oval granular masses which may be deeply fissured and surrounded by sharply defined refractive 

 and non-refractive lamellae. The irregular clefts when present increase in size, and the smaller 

 fissures radiating from them penetrate to all parts of the grain. If clefts are not present in the 

 untreated grain at the position of the hilum, either irregularly branched ones are formed there, 

 or the central mass is gelatinized with the formation of many refractive granules, and delicate 

 fissures radiate from this region towards the margin. The gelatinized grains are much swollen and 

 the outline is quite irregular. Some of the grains are completely gelatinized, except a few refractive 

 granules eml)edded in a gelatinous mass surrounded by the outermost laj'ers. In other grains, 

 more layers of lamellae have partly resisted gelatinization, and these are much convoluted, and a deep 

 longitudinal cleft frequently passes through the center of the mass. Occasionally the cleft divides the 

 grain at one or both ends. There are refractive granules in the folds of the gelatinized grain. 



With ferric chloride the grains begin to react in 4 minutes. A few are gelatinized in 7 minutes, 

 about one-tenth in 30 minutes, and about one-fifth in an hour. The hilum if unfissured becomes 



