520 



DATA OF PROPERTIES OF STARCHES OF PARENT- AND HYBRID-STOCKS. 



those of N. poeticus omatus, and the irregularities are 

 due to the same causes: (1) Irregular depressions and 

 elevations in the surface and margin; (2) more grains 

 with small, irregular, rounded protuberances from vari- 

 ous points on the margin; (3) pressure facets at the 

 distal end and sides; (4) fewer regular depressions and 

 elevations of the surface giving a fluted appearance; (5) 

 the same number of grains, with a small notch at the 

 proximal end, or 2 small notches, one on each side of the 

 proximal apex. The conspicuous forms are irregular 

 ovoid, slender lenticular, plano-convex, dome-shaped, 

 nearly round, scalene-triangular and other triangular 

 forms, and slender elliptical. The additional forms are 

 irregularly polygonal, clam-shell-shaped, pyriform, and 

 reniform. The grains are not flattened. 



The hilum is even more often fissured than in N. poeti- 

 cus omatus, and when not fissured it appears as a rather 

 small, round, or lenticular spot which is not so distinct 

 as in N. poeticus omatus. The fissures are as deep and 

 even more extensive, but less often branched, than in 

 N. poeticus omatus and have the following forms: (1) 

 Cruciate-, T-, or Y-shaped; (2) an irregularly stellate 

 group of fissures radiating in all directions from the 

 hilum; (3) a single, straight, transverse, or oblique line. 

 The hilum is sometimes centric, but is commonly eccen- 

 tric from 0.45 to 0.28, usually 0.38, of the longitudinal 

 axis. 



The lamella; are not so distinct or so coarse as in 

 N. poeticus omatus, and conform in general to the shape 

 of the outline of the grain, but only near the margin do 

 they follow the irregularities of the contour. In the 

 grains which have both primary and secondary starch, 

 they are usually moderately distinct in the secondary 

 portion and invisible in the primary deposit. The num- 

 ber counted on some of the larger grains varies from 

 8 to 18, usually 12. 



In size the grains vary from the smaller which are 

 5 by 5/i, to the larger broad forms which are 50 by 50/*, 

 and 46 by 50/*, and the rare larger elongated forms, which 

 are 46 by 38/i. The common sizes are 32 by 30*i and 

 30 by 34/*. 



Polariscopio Properties. 



The figure is usually distinct, but is even less often 

 well defined than in N. poeticus omatus. The lines in- 

 tersect one another at angles of widely varying size and 

 are much more apt to be bisected and bent than in N. 

 poeticus omatus. The figure also much less. often has 

 the form of a cross in N. poeticus omatus — hyperbolas 

 and longitudinal lines bisected at both ends being not 

 uncommon. 



The degree of polarization varies from low to very 

 high (value 40). Tbe value is less than in N. poeticus 

 omatus as there are fewer grains in which the degree of 

 polarization is very high. There is also more variation 

 in the same aspect of a given grain. 



With selenite the quadrants are not well defined and 

 are more irregular in shape and unequal in size than in 

 N. poeticus omatus. The colors are not so pure, and 

 there are fewer grains in which a greenish tinge is ob- 

 served than in N. poeticus omatus. 



Iodine Reactions. 

 Willi 0.?. r > per cent Lugol's solution the grains color a 

 moderate violet tinged with blue (value 45), somewhat 

 deeper and with more of a bluish tint than in N. poeticus 



omatus. The color deepens with moderate rapidity until 

 it is very deep, becoming, at the same time, more bluish 

 in tint. With 0.125 per cent Lugol's solution, the grains 

 color a light violet, not so light as in N. poeticus omatus. 

 The color deepens with moderate rapidity until the grains 

 are deeply colored, assuming more of a bluish tinge than 

 in N. poeticus omatus. After heating in water until all 

 the grains are gelatinized and then adding a 2 per cent 

 Lugol's solution, the gelatinized grains all color a moder- 

 ate indigo, less than in N. poeticus omatus ; and the solu- 

 tion a deep indigo-blue, more than in i\ T . poeticus omatus. 

 If the preparation is boiled for 2 minutes, and then 

 treated with an excess of 2 per cent Lugol's solution, 

 most of the grain-residues color a light to moderate 

 indigo-blue, less than in N. poeticus omatus, and in a 

 few only the capsules are colored. The capsules all color 

 a red or reddish violet, and the solution a very deep 

 indigo-blue, the same as in N. poeticus omatus. 



Aniline Reactions. 



With gentian violet the grains color very lightly at 

 once, and in half an hour they are light to moderately 

 colored (value 35), somewhat more than in N. poeticus 

 omatus. The grains are all stained with equal intensity, 

 and there is no variation in the same aspect of an indi- 

 vidual grain. 



With safranin the grains color very lightly at once, 

 and in half an hour they are moderately colored (value 

 50), somewhat more than in N. poeticus omatus. The 

 grains are all stained with equal intensity, and there 

 is no variation in the same aspect of the individual grain. 



Temperature Reactions. 

 The temperature of gelatinization of the majority 

 of the grains is 67° to 69° C, and of all is 71° to 73° 

 C, mean 72° C. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins in rare 

 grains in 2 minutes. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains and 

 total starch in 5 minutes ; in about 3 per cent of the grains 

 and 6 per cent of the total starch in 15 minutes; in about 

 5 per cent of the grains and 9 per cent of the total starch 

 in 30 minutes; in about 6 per cent of the grains and 11 

 per cent of the total starch in 45 minutes ; in about 10 per 

 cent of the grains and 17 per cent of the total starch in 

 60 minutes. (Chart D 259.) 



The hilum is indistinct except in the few grains 

 in which a rather large bubble is formed. The lamella: 

 are at first indistinct, but gradually become moderately 

 distinct in most of the grains as in N. poeticus omatus. 

 The grains become more refractive in appearance after 

 the addition of the reagent, and the first part to be so 

 affected is a rather narrow band of starch at the margin 

 which is narrower and less refractive than a similar band 

 in N. poeticus omatus. Gelatinization begins at various 

 discrete points on the margin and proceeds in two ways. 

 The method seen in the majority of the grains is very 

 similar to that described for the grains of N. poeticus 

 omatus. The marginal material is gelatinized nearly 

 to the proximal end on either side, without, however, 

 being partially separated from the rest of the grain by a 

 fissure as in N. poeticus omatus. Gelatinization now 

 proceeds inward, the ungelatinized starch assumes a 



