544 



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



grain and converges from these two points towards the 

 hilum, which, is centric; when the hilum is reached it 

 swells, separating the two portions of material on either 

 side of it. The broad grains are very resistant and only 

 occasionally is one gelatinized. In such grains the process 

 is the same as that described for the rapidly reacting 

 grains, except that it is much slower, is not preceded 

 by so much fissuring of the grain, and the grain is not 

 always completely gelatinized. 



The gelatinized grains are much swollen, have thick 

 capsules, and are not greatly distorted, but retain some 

 resemblance to the form of the untreated grain. 



Comparison of the chloral hydrate reactions between 

 N. poeticus ornatus and N. telemonius plenus shows : 



The hilum is not so distinct, and a bubble is less often 

 formed there than in N. telamonius plenus. The la- 

 mellae are more distinct and are visible in more grains, 

 and the grains are somewhat more refractive in appear- 

 ance after the addition of the reagent than in IV. tela- 

 monius plenus. Gelatinization proceeds according to two 

 methods, but there is no marked distinction between less 

 resistant and more resistant grains. In the first, which 

 is seen in the great majority of the grains, gelatinization 

 begins at various discrete points on the margin and is 

 preceded by a pitted appearance of the surface of the 

 grain. It proceeds from the initial points all around the 

 margin until only the proximal margin is not gelatinized, 

 and then inward, the ungelatinized starch being in- 

 vaded by fissures which separate off small particles until 

 the hilum is reached. The bubble if present swells, 

 shrinks, and finally disappears and the hilum swells, 

 and then the starch at the proximal end is gelatinized. 

 The lenticular grains are gelatinized in the same way 

 described from the lenticular grains of N. telamonius 

 plenus. The gelatinized grains are more swollen, their 

 capsules are not so thick, and they are more distorted 

 than in N. telamonius plenus. 



The reaction with chromic acid begins in 30 seconds. 

 Complete gelatinization occurs in about 0.5 per cent of 

 the entire number of grains and 26 per cent of the total 

 starch in 15 minutes ; in about 10 per cent of the grains 

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

 about 75 per cent of the grains and 95 per cent of the 

 total starch in 45 minutes; in about 95 per cent of the 

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

 in 60 minutes. (Chart D 249.) (See footnote, page 516.) 

 The hilum is distinct, and the lamellae are moder- 

 ately distinct in most of the grains, but not visible in 

 some. Gelatinization begins at the hilum and progresses 

 according to but one method. The portion immediately 

 surrounding the hilum, which usually represents the pri- 

 mary starch formation, is cracked and divided into 3 or 

 4 pieces that are covered by coarse striae. The rest 

 of the grain, which is usually distinctly a secondary 

 formation, is less coarsely but still very distinctly striated. 

 The grain swells and the cracks widen, in some grains, 

 the primary starch is gelatinized at once and the second- 

 ary starch is pushed to the margin, where it forms a 

 striated and lamellated band which gradually becomes 

 apparently homogeneous. It then grows thinner and 

 more nearly transparent, but is dissolved before gelatini- 

 zation is complete. In other grains the primary starch 

 is cracked into 2 or 3 pieces, which are later subdivided, 

 and as the grain swells and the secondary starch is pushed 



to the margin, the particles are scattered and arranged 

 around the inner border of the marginal band, where 

 they remain until part of the margin is dissolved and the 

 contents of the capsule flow out of the opening and 

 dissolve in the surrounding reagent. 



The grains all begin to dissolve before gelatinization 

 is complete, so that the character of a completely gela- 

 tinized grain can not be determined. 



Comparison of the chromic-acid reactions between IV. 

 poeticus ornatus and IV. telamonius plenus shows : 



The hilum and lamellae as a rule are not so distinct, 

 gelatinization progresses according to two methods, one 

 of which is different from the one described for the 

 grains of IV. telamonius plenus. In the first method 

 several fissures proceed longitudinally from the hilum 

 to the distal margin, dividing this part of the grain into 

 granules and the rest of the grain is distinctly striated. 

 Gelatinization then commences and the inner material 

 becomes granular, while the rest of the material forms 

 a marginal band consisting of two parts which is slowly 

 gelatinized. In the second method, which is seen only 

 in a very small minority of the grains and which is the 

 same as that described for some of the grains of IV. tela- 

 monius plenus, in that the primary does not gelatinize 

 before the secondary starch, but is resistant and is 

 broken up into granules which are scattered around the 

 inner border of the marginal band. Most of the grains 

 are completely gelatinized before they are dissolved, and 

 in this differ from those of IV. telamonius plenus. 



The reaction with pyrogallic acid begins in 1 minute. 

 Complete gelatinization occurs in less than 0.5 per cent 

 of the entire number of grains and 2 per cent of the total 

 starch in 5 minutes ; in about 2 per cent of the grains and 

 33 per cent of the total starch in 15 minutes; in about 

 39 per cent of the grains and 73 per cent of the total 

 starch in 30 minutes ; in about 50 per cent of the grains 

 and 84 per cent of the total starch in 45 minutes; in 

 about the same percentage of the grains and 90 per cent 

 of the total starch in 60 minutes. (Charts D 295, 

 D296.) 



The hilum becomes distinct, unaccompanied by the 

 formation of a bubble. The lamellae are moderately 

 distinct in all the grains. Gelatinization begins at the 

 hilum and progresses according to three methods. In 

 the first, which is seen in a majority of the grains, the 

 primary material immediately surrounding the hilum 

 is split into 5 or 6 portions, which are usually subdivided 

 into many coarse granules and widely scattered as the 

 grain swells, but which sometimes remain clumped to- 

 gether in the center of the grain, apparently unaffected 

 by the reagent. The secondary starch becomes homo- 

 geneous in appearance and somewhat more refractive in 

 small scattered spots and is gelatinized slowly, the more 

 resistant portion forming a nearly homogeneous-looking, 

 refractive band at the margin in which a suggestion of 

 lamellar arrangement is sometimes seen. Around the 

 inner border of this band are usually scattered the 

 granules of the primary starch. The marginal band 

 grows slowly thinner and more nearly transparent and is 

 finally gelatinized; the granules of the primary starch 

 grow smaller more slowly, become more refractive, and 

 finally disappear. In the second method two furrows or 

 fissures extend from the hilum on either side to the 



