550 



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



Comparison of the chloral-hydrate reactions between 

 N. poeticus poetarum and N. princess mary shows : 



A bubble is less frequently found at the hilum, and 

 the lamellae, though at first not visible as in N. princess 

 mary, later become moderately distinct. In all the grains 

 the portion at the margin is the first part to become more 

 refractive after the addition of the reagent instead of the 

 whole grain becoming equally refractive, as in so many 

 grains of N. princess mary. Gelatinization begins at 

 various points on the margin, not confined to the distal 

 end as in most of the grains of N. princess mary, and 

 proceeds in two ways, the one occurring in the minority 

 of the grains being the same as that described for the 

 broad resistant grains of N. princess mary. The other 

 method which occurs in the majority of the grains is not 

 seen in any grains of N. princess mary. The marginal 

 deposit is all gelatinized except a narrow strip just at 

 the proximal end. Then gelatinization, preceded by a 

 pitted appearance of the ungelatinized starch, follows 

 division of this strip by numerous fissures. These fissures 

 split off small particles, which float away and are gela- 

 tinized. When the hilum is reached it swells suddenly 

 and the proximal end is the last to be gelatinized. The 

 gelatinized grains are more swollen and have thin cap- 

 sules. They are more distorted than those of N. princess 

 mary. 



The reaction with chromic acid begins in 1 minute. 

 Complete gelatinization occurs in less than 0.5 per cent 

 of the grains and 2 per cent of the total starch in 5 min- 

 utes ; in about 1 per cent of the grains and 25 per cent 

 of the total starch in 15 minutes; in about 5 per cent of 

 the grains and 70 per cent of the total starch in 30 

 minutes; in about 30 per cent of the grains and 90 per 

 cent of the total starch in 45 minutes; in about 60 per 

 cent of the grains and 98 per cent of the total starch in 

 60 minutes. (Chart D 300.) (See footnote, page 516.) 

 The hilum is distinct and a bubble is now formed 

 there. The lamellse are moderately distinct in some of 

 the grains and not visible in others. Gelatinization be- 

 gins at the hilum and progresses according to two 

 methods. In the first, which is noted in the great major- 

 ity of the grains, 2 furrows are seen extending trans- 

 versely from the hilum on either side to the margin. The 

 starch included between these furrows, the hilum, and the 

 margin is divided up into granules by fine, irregular fis- 

 sures or channels which radiate from the hilum to the 

 margin. The granules so formed are especially large, 

 refractive, and distinct near the hilum. The starch at the 

 proximal end and sides nearby becomes indistinctly 

 striated, and as the distal material is gelatinized and the 

 grain swells it is pushed to the margin, where it forms a 

 compact, rather coarse distinctly striated band which 

 later unites with a similar band formed of the more re- 

 sistant distal starch all around the margin. The stria- 

 tion gradually disappears and the band becomes thinner 

 and more nearly transparent, and finally is gelatinized, 

 leaving only the capsule, the proximal portion being the 

 last to be gelatinized. In the second method the primary 

 material around the hilum is divided into 3 or 4 pieces 

 by fissures and these pieces stay crumped together as the 

 rest of the grain gelatinizes and then slowly become 

 smaller, more refractive, and more widely separated, and 

 finally disappear. The secondary starch meanwhile is 

 gelatinized from within outward, the less resistant sub- 



stance swelling and forcing the more resistant deposit to 

 the margin, where it forms a striated and often lamel- 

 lated band which gradually grows thinner and loses its 

 striated appearance and is finally gelatinized. The 

 grains are nearly always completely gelatinized before 

 solution takes place. The gelatinized grains are much 

 swollen, have rather thin capsules, and are somewhat 

 distorted. 



Comparison of the chromic-acid reactions between 

 N. poeticus poetarum and N. princess mary shows: 



The hilum and lamellae are somewhat more distinct, 

 and gelatinization progresses according to two types, 

 one of which has been already described for the majority 

 of the grains of N. princess mary. The latter is seen in 

 more grains than in N. princess mary and differs from 

 the method in that grain in that there is not so much 

 irregular fissuring and the bands of resistant material do 

 not so often extend around the whole margin. In the 

 second type a number of fissures extend from the hilum 

 to the distal margin, dividing the starch in their path 

 into irregular granules. This granular portion now be- 

 gins to gelatinize and the grain swells and the more 

 resistant starch is pushed to the margin, where it forms 

 a striated band which is thinner at the distal margin 

 and which gradually loses its striated appearance and 

 becomes thinner and more nearly transparent. The gela- 

 tinized grains are much swollen, have thinner capsules 

 and are more distorted than in N. princess mary. They 

 often are dissolved before gelatinization is complete. 



The reaction with pyrogallic acid begins in 2 min- 

 utes. Complete gelatinization occurs in less than 0.5 per 

 cent of the entire number of grains and 3 per cent of 

 the total starch in 5 minutes ; in about 6 per cent of the 

 grains and 40 per cent of the total starch in 15 minutes ; 

 in about 43 per cent of the grains and 77 per cent of the 

 total starch in 30 minutes; in about 57 per cent of the 

 grains and 87 per cent of the total starch in 45 minutes ; 

 in about 67 per cent of the grains and 95 per cent of the 

 total starch in 60 minutes. (Charts D 301 and D 302.) 



The hilum is distinct. The lamellae are moderately 

 distinct, and a lamellated appearance often persists for a 

 considerable time at the margin of the gelatinized grains. 

 Gelatinization begins at the margin and progresses ac- 

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

 great majority of the grains, 2 refractive furrows extend 

 transversely or, rarely, obliquely, from either side of 

 the hilum nearly to the margin and the starch included 

 between them, the hilum and all but the portion imme- 

 diately at the margin are first irregularly divided by 

 fine, branching fissures and then become a refractive 

 homogeneous-looking mass which slowly is gelatinized 

 from the hilum outward. The more resistant starch 

 at the proximal end and sides nearby is striated and, 

 then as the grain swells, forms in connection with a 

 thinner band of starch forming the rest of the margin, 

 a refractive striated band which very slowly grows thin- 

 ner and more refractive and finally is completely gela- 

 tinized. In the second method the primary starch is 

 split into a number of small particles or rather coarse 

 granules, and the secondary starch becomes finely striated 

 and the less resistant portion is gelatinized and the whole 

 grain slowly swells. The more resistant part of the 

 primary starch is pushed to the margin, where it forms 

 a rather homogeneous-looking, refractive band around 



