622 



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



described for that starch. The conspicuous forms are 

 broad and narrow ovoid, and ellipsoidal with flattened 

 or rounded distal end. The additional forms are pyri- 

 form, clam-shell-shaped, triangular with rounded base, 

 and nearly round. The tendency of the grain to be 

 narower at the proximal than at the distal end which is 

 so marked in L. chalcedonicum is present in this starch, 

 but is not so marked. The broad forms are somewhat 

 flattened as in L. chalcedonicum and when seen on edge 

 have an elongated ovoid or ellipsoidal shape. 



The hilum as in L. chalcedonicum is a small rather 

 indistinct, round, or lenticular spot. It is more often 

 fissured than in L. chalcedonicum, but the fissures have 

 the same form, except that they may be curved instead 

 of straight. The hilum is eccentric from 0.4 to 0.03, 

 commonly 0.17, of the longitudinal axis. It is usually 

 somewhat less eccentric than that of the grains of L. 

 chalcedonicum. 



The lamellce are as fine but somewhat more distinct 

 than those of L. chalcedonicum. The broad refractive la- 

 mella; described under L. chalcedonicum are more numer- 

 ous than in this starch, and there is often a band of 

 3 or 4 such lamellae across the distal one-third of the 

 grain. Otherwise they are the same as those of L. chair 

 cedonicum. The number counted on the larger grains 

 varies from 24 to 46, usually 42, somewhat less than in 

 the other parent. 



In size the grains vary from the smaller which are 

 6 by 6/x, to the larger broad forms which are 64 by 50/x, 

 and the larger narrow forms which are 64 by 30/*, in 

 length and breadth. The common size is 40 by 30/x.. 

 The sizes of the corresponding types are less than those 

 of either parent. 



Polariscopic Properties. 



The figure is as distinct as in L. chalcedonicum and 

 somewhat better defined. The lines more often cross at a 

 right angle than in L. chalcedonicum, or at an acute 

 angle whose size varies less in different grains than in 

 that starch. They are less often bent or bisected than in 

 L. chalcedonicum. The figure, also, is less often in the 

 form of a conjugate hyperbole, or of a long line bisected 

 at both ends than in that starch. 



The degree of polarization varies from low to high 

 (value 65), more than in L. chalcedonicum, as there 

 are more grains in which it is high and fewer in which 

 it is moderate than in that starch. There is the same 

 amount of variation in a given aspect of an individual 

 grain. 



With selenite the quadrants are somewhat more clear- 

 cut, and are less unequal in size and irregular in shape. 

 The colors are more often pure than in L. chalcedonicum. 



Iodine Reactions. 

 With 0.25 per cent Lugol's solution the grains color 

 a moderate to deep blue violet (value 65), more than in 

 L. chalcedonicum. The color deepens very rapidly until 

 it is very deep and more bluish. With 0.125 per cent 

 Lugol's solution the grains all color a moderate violet 

 tinged with blue, more than in L. chalcedonicum. The 

 color deepens rapidly until it is very deep and more 

 bluish. After heating in water until the grains are all 

 completely gelatinized and treating with a 2 per cent 

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

 ate indigo, less than in L. chalcedonicum, and the solution 



a deep indigo, more than in L. chalcedonicum. If the 

 preparation is boiled for 2 minutes and then treated 

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

 majority of the grain-residues color a very light indigo, 

 less than in L. chalcedonicum, and some do not color at 

 all ; the capsules a red or a reddish violet as in L. chalce- 

 donicum; and the solution a very deep indigo as in L. 

 chalcedonicum. 



Aniline Reactions. 



With gentian violet the grains all color very lightly 

 at once, and in 30 minutes are moderately to very deeply 

 colored (value 80), much more than in L. chalcedonicum. 

 As in that starch they are often more deeply colored 

 at the distal than at the proximal end. 



With safranin the grains all color very lightly at 

 once, and in 30 minutes they are moderately to very 

 deeply colored (value 80), much more than in L. chalce- 

 donicum. As in that starch, they are often more deeply 

 colored at the distal than the proximal end. 



Temperature Reactions. 

 The temperature of gelatinization of the majority of 

 the grains is 57° to 58.7° C, and of all is 60° to 62° C, 

 the mean is 61° C. lower than those of the other parent. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins in 1 min- 

 ute. Complete gelatinization occurs in about 14 per cent 

 of the entire number of grains and 34 per cent of the total 

 starch in 5 minutes; in about 34 per cent of the grains 

 and 74 per cent of the total starch in 15 minutes; in 

 about 66 per cent of the grains and 88 per cent of the 

 total starch in 30 minutes; in about 77 per cent of the 

 grains and 92 per cent of the total starch in 45 minutes ; 

 and in about 88 per cent of the grains and 95 per cent of 

 the total starch in 60 minutes. (Chart D 3C7.) 



The hilum becomes distinct, attended by the forma- 

 tion of a bubble in fewer grains than in L. chalcedoni- 

 cum. The lamella; are usually not visible as in L. chalce- 

 donicum, but in some grains they are moderately dis- 

 tinct. Gelatinization, unlike L. chalcedonicum, usually 

 begins at the proximal end and then quickly at one or 

 two points on the distal margin. It proceeds first all 

 along the distal margin, and then from both ends towards 

 the center of the grain. Gelatinization is preceded by a 

 pitted appearance of the surface of the grain and an 

 occasional particle is separated from the ungelatinized 

 material and gelatinized. This does not occur so fre- 

 quently as in L. chalcedonicum and the particles are 

 larger than in that starch. The last part to be gela- 

 tinized is that just distal to the hilum and this is gela- 

 tinized as is the rest of the grain. The gelatinized 

 grains are as much swollen as in L. chalcedonicum, but 

 have thicker capsules and are even more distorted than in 

 that starch. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 3 per cent of 

 the entire number of grains and 64 per cent of the total 

 starch in 3 minutes; in about 25 per cent of the grains 

 and 77 per cent of the total starch in 5 minutes ; in about 

 70 per cent of the grains and 93 per cent of the total 

 starch in 15 minutes; and in about 98 per cent of the 

 grains and in more than 99 per cent of the total starch 

 in 30 minutes. (Chart D 368.) 



