390 



STARCHES OF LEGUMINOS^E. 



There may be several hila in each grain, grouped rather irregularly in a central non-lamellated 

 space of the same general outline as the margin of the grain. These hila are small and indistinct and 

 their number can not be exactly determined. This space is often fissured. Frequently there is a 

 single, long, fairly straight fissure extending in the longitudinal axis. In some grains the fissure 

 extends the length of the grain and it may be ragged or curved or variously modified. 



The lamellce are not, as a rule, very distinct. They appear as continuous, rather fine rings which 

 follow closely the marginal outline. There are 8 to 10 on the larger grains. 



The grains vary in size from the smaller, which are 10 by 6^ in length and breadth, to the 

 larger, which are 32 by 26/* and 32 by d2n in length and breadth. The common size is 20 by 18/u in 

 length and breadth. 



Polariscopic Properties. — The figure is usually decidedly eccentric. The lines almost invari- 

 ably int<?rsect obliquely. They are broad, generally not clear-cut, more or less modified by fissures, 

 and sometimes bisected. Rarely a bean type of figure (single line with bisected ends) is observed. 



The degree of polarization is high to very high, 

 varying more or less in different parts of the same aspect 

 of a given grain. In some grains only small parts of the 

 quadrants are light. 



With selenite the quadrants are usually fairly well 

 defined, unequal in size, and irregular in shape. The 

 colors are generally pure; the yellow is sometimes not 

 pure throughout the entire grain. 



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

 tion the grains color a very light violet, some more deeply 

 than others, and in 5 minutes they become a deep blue- 

 violet; with 0.125 per cent solution the grains show 

 at once a faint trace of red-violet, which in 5 minutes 

 deepens to a light reddish-violet; the color is deeper in 

 some grains than in others. After heating in water until 

 all the grains are completely gelatinized, the solution 

 colors a deep indigo-blue and the grains a bright indigo- 

 blue on the addition of iodine. When the grains are 

 boiled for 2 minutes and then treated with iodine, the 

 solution becomes a deeper indigo-blue; some of the 



grain-residues not coloring at all, while others become a light blue with a reddish tint or a red- 

 violet. With an excess of iodine the grain-residues color a deep reddish-purple and the capsules 

 a wine-red. 



Staining Reactions. — With gentian violet most of the grains show a faint trace of violet at once 

 and in 30 minutes they are lightly stained, some more deeply than others. 



With safranin most of the grains exhibit a faint trace of pink at once, and in 30 minutes they 

 are lightly stained. There is a fairly deep pink color in the dehcate fissures of the grains, but none 

 in the deep fissures. 



Temperature Reaction. — The temperature of gelatinization is 73° to 75° C, mean 74°. 



Effects of Variants Reagents.— With chloral hydrate-iodine a few grains, which are either injured 

 or partially digested or eroded, begin to react at once and a small number are gelatinized in a minute. 

 About one-third are gelatinized in 10 minutes, one-half in 15 minutes, two-thirds in 30 minutes, 

 and three-fourths in 60 minutes. The reactions are the same qualitatively as in Vicia. 



The reaction with chromic acid begins in 30 seconds to IJ^ minutes and is over in 7 minutes. 

 The reaction is qualitatively the same as in Vida. 



The reaction with pyrogallic acid begins in many of the grains in 13^ minutes and practically 

 all are completely gelatinized in 20 minutes. The effects are qualitatively the same as in Vicia. 



With ferric chloride the reaction begins in a few grains in 5 minutes and is over in one-fifth 

 in 30 minutes and in nearly one-fourth in an hour. The effects are qualitatively the same as in 

 Vicia. 



The reaction with Purdy's sohition begins slightly in a few in 3 minutes, about one-fourth are 

 partially gelatinized in 30 minutes, and about three-fifths are partially gelatinized in an hour. The 

 effects are qualitatively the same as in Vicia. 



Curve of Reaction-Intenaities of Starch of Dolichos lablab. 



