726 



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



not color at all, but some color a very light to a light 

 indigo; the capsules all color a red or a reddish violet, 

 and the solution a very deep indigo-blue. 



ANILINE REACTIONS. 



With gentian violet the grains all color very lightly 

 at once, and in 30 minutes they are lightly to deeply 

 colored (value 50). A few of the grains are lightly 

 colored, most of them are moderately colored, and a few 

 are deeply colored. There is no variation in depth of 

 color in different parts of an individual grain. 



With safmnin the grains all color very lightly at 

 once, and in 30 minutes they are moderately to deeply 

 colored (value 60). Most of the grains are moderately 

 colored, and some are moderately to deeply colored. 

 There is no variation in the depth of color in different 

 parts of an individual grain. 



TEMPERATURE REACTIONS. 



The temperature of gelatinization of the majority of 

 the grains is 60 to 61.5 C., and of all 64.3 to 65.8 C., 

 mean 65 C. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins in rare 

 grains in 30 seconds. Complete gelatinization occurs in 

 about 40 per cent of the entire number of grains and 

 55 per cent of the total starch in 5 minutes; in about 

 80 per cent of the grains and 90 per cent of the total 

 starch in 15 minutes ; in about 97 per cent of the grains 

 and in more than 99 per cent of the total starch in 30 

 minutes. (Chart D 553.) 



The hilum becomes distinct, unattended by the for- 

 mation of a bubble, except in a few grains. The lamellae 

 are, at first, not visible, but later become distinct and 

 more refractive just before gelatinization. The grain 

 is more refractive, the first part to show this change is a 

 band of starch at the margin which is broad at the distal 

 end. Gelatinization begins at the distal margin and at 

 the ends of any projections from the grain and progresses 

 according to two methods. In the first, which is seen in 

 the great majority of the grains, gelatinization begins 

 at the proximal end shortly after the distal margin has 

 been gelatinized, the hilum swelling suddenly and rap- 

 idly, and the bubble, if present, swelling also, then shrink- 

 ing and disappearing. Gelatinization then advances from 

 these two points, preceded by small cracks and fissures 

 in the ungelatinized starch. Progress is more marked 

 at the margin than elsewhere, and the marginal starch is 

 all gelatinized before the central starch. Finally, only a 

 small portion of the grain, which is just distal to the 

 hilum, is ungelatinized, and this is split into 2 or 3 

 pieces which are widely separated and gelatinize inde- 

 pendently of one another. In the second method, which 

 is seen in a moderate number of the elongated grains, 

 gelatinization begins at the distal end and progresses 

 smoothly from this point toward the proximal end with- 

 out any cracking or fissuring of the grain. The proximal 

 portion is the last to be gelatinized. The gelatinized 

 grains are much swollen, have rather thin capsules, 

 and are much distorted, but show some resemblance to 

 the form of the untreated grain. 



The reaction with chromic acid begins in a few grains 

 in 15 seconds; in about 76 per cent of the grains and 



95 per cent of the total starch in 5 minutes ; in 100 per 

 cent of the grains and total starch in 15 minutes. (Chart 

 D 554.) 



The hilum becomes distinct in all the grains, rarely 

 attended by the formation of a bubble which as the 

 grain swells soon shrinks and disappears. The lamellse 

 become very distinct; gelatinization begins at the hilum 

 and progresses according to two methods. In the first, 

 which is seen in all the broad forms, which are also in 

 the majority, 2 furrows or actual fissures are seen to 

 extend transversely or slightly obliquely from the hilum 

 on either side to the margin and the hilum begins to 

 enlarge. The starch distal to these 2 fissures is first criss- 

 crossed by many irregular fissures, then as the hilum and 

 the grain continue to enlarge it is split into 3 or 4 pyra- 

 midal masses by wedge-shaped fissures and the starch in 

 these pyramids eventually forms an irregularly granular 

 mass just proximal to a broad, smooth band at the distal 

 margin. The hilum meanwhile has been enlarging, espe- 

 cially toward the proximal end, and the starch here and 

 at the sides nearby forms at the margin a thick, homoge- 

 neous-looking, refractive band which becomes thinner and 

 hyaline in appearance, especially at the proximal apex. 

 The capsule is dissolved at this point, and the grain dis- 

 solves from this region distally, the last part to be dis- 

 solved is often the granular mass at the distal end as 

 before described. In the second method, which is seen in 

 the elongated grains that are in the minority, the hilum 

 begins to enlarge and 2 furrows or fissures extend ob- 

 liquely from either side of the hilum quite to the distal 

 margin. In some of the grains the part of the grain 

 included between these fissures becomes irregularly fis- 

 sured nearly to the distal margin where, however, a broad 

 band of starch remains undisturbed. In others the por- 

 tion proximal to this broad band is not irregularly fis- 

 sured, but divided into filaments by fissures which slant 

 proximally from the 2 original furrows or fissures on 

 either side to the longitudinal axis of the grain. As the 

 hilum continues to enlarge, a part of the fissured portion 

 is gelatinized and the rest forms an irregularly granular 

 mass just above the broad band of starch at the distal 

 margin. The starch at the proximal end and sides forms 

 a thick, homogeneous-looking band which is thinner at 

 the proximal apex. It is dissolved at this point, dissolu- 

 tion proceeding distally until the whole grain is in solu- 

 tion, the granular starch at the distal end being the last 

 to be dissolved. 



The reaction with pyrogallic acid begins in 30 sec- 

 onds. Complete gelatinization occurs in about 30 per 

 cent of the entire number of grains and 86 per cent of the 

 total starch in 5 minutes; in about 68 per cent of the 

 grains and 95 per cent of the total starch in 15 minutes ; 

 in about 90 per cent of the grains and 99 per cent of the 

 total starch in 30 minutes. (Chart D 555.) 



The hilum becomes very distinct, unattended by the 

 formation of a bubble. The lamellse become more dis- 

 tinct at first, but later are obscured. Gelatinization be- 

 gins at the hilum and progresses according to two 

 methods. The first is seen in the broad forms which 

 constitute a majority of all the grains, the hilum begins 

 to enlarge and 2 furrows are seen to extend obliquely, 

 rarely transversely, from the hilum on either side to the 

 margin, and the starch proximal to these furrows forms 

 a homogeneous-looking, refractive band at the proximal 



