670 



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



the grains and 98 per cent of the total starch in 15 

 minutes ; in about 84 per cent of the grains and 99 per 

 cent of the total starch in 30 minutes; little if any 

 further advance occurs in 45 and 60 minutes, respec- 

 tively. ( Chart D 448.) The margin of a smaller per- 

 centage of grains is resistant than in /. persica var. 

 purpurea, but a proportionately larger number of entire 

 grains are resistant at 5 minutes than in I. persica var. 

 purpurea; hence, the difference between the complete 

 and total percentage of gelatinization is not so great as 

 in I. persica var. purpurea. 



The reaction with potassium iodide begins imme- 

 diately. Complete gelatinization occurs in about 85 per 

 cent of the entire number of grains and 98 per cent of 

 the total starch in 5 minutes ; in about 94 per cent of the 

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

 in 15 minutes. (Chart D 449.) 



The hilum is as distinct as in I. persica var. purpurea, 

 but a bubble is not so often formed there. The lamellae 

 are somewhat more distinct than in I. persica var. pur- 

 purea. Gelatinization begins at the hilum which en- 

 larges somewhat, and in some grains fine strise may be 

 seen to radiate from the hilum throughout the grain to 

 the margin. This striation is not nearly so marked 

 as in /. persica var. purpurea. The hilum continues 

 to enlarge and also the grain, and the more resistant 

 starch is pushed to the margin, where it forms a lamel- 

 lated and usually a non-striated band, differing from 

 I. persica var. purpurea in which grains the marginal 

 band was striated but not often lamellated. In the 

 elongated grains, the reaction is very close to that de- 

 scribed under /. persica var. purpurea, except that there 

 are not so many nor such refractive granules formed 

 and these granules are not so resistant as in /. persica 

 var. purpurea. The gelatinized grains are somewhat 

 swollen, and have thicker walls, and are not so much dis- 

 torted as in I. persica var. purpurea, and retain much 

 more of the form of the untreated grain. 



The reaction with potassium sulpliocyanate begins 

 immediately. Complete gelatinization occurs in about 

 87 per cent of the entire number of grains and in more 

 than 99 per cent of the total starch in 2 minutes ; in about 

 95 per cent of the grains and in more than 99 per cent 

 of the total starch in 5 minutes. (Chart D 450.) 



The reaction with potassium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 5 per 

 cent of the e,ntire number of grains and 22 per cent of 

 the total starch in 5 minutes ; in about 7 per cent of the 

 grains and 33 per cent of the total starch in 15 minutes; 

 in about 11 per cent of the grains and 37 per cent of the 

 total starch in 30 minutes; in about 14 per cent of the 

 grains and 40 per cent of the total starch in 45 minutes ; 

 little if any further advance in 60 minutes. (Chart 

 D451.) 



The reaction with sodium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 77 per 

 cent of the entire number of grains and 95 per cent of 

 the total starch in 2 minutes; in more than 99 per cent 

 of the grains and total starch in 5 minutes. (Chart 

 D452.) 



The hilum and lamella? are more distinct than in 

 I. persica var. purpurea, and 2 refractive fissures extend- 

 ing from the hilum towards the distal margin appear in 

 very few grains, many less than in /. persica var. pur- 



purea. Gelatinization begins at the hilum as in /. per- 

 sica var. purpurea, and the processes of gelatinization in 

 the two types of grains present are very similar to those 

 described under /. persica var. purpurea. The main 

 differences noted are that in these grains the starch 

 immediately around the hilum is more irregularly and 

 extensively fissured than in 7. persica var. purpurea, so 

 that there is a greater persistence of resistant granules in 

 the gelatinized grains; that the striae with which the 

 majority of the grains are covered are coarser and more 

 distinct ; that the granules which are formed at the mar- 

 gin are coarser; and that the lamellated appearance of 

 this marginal band persists for an even longer time. 

 The gelatinized grains are more swollen, and the capsules 

 are thinner but less distorted, than in /. persica var. 

 purpurea. 



The reaction with sodium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 54 per 

 cent of the entire number of grains and 79 per cent 

 of the total starch in 5 minutes ; in about 83 per cent of 

 the grains and 96 per cent of the total starch -in 15 

 minutes; in about 92 per cent of the grains and 98 per 

 cent of the total starch in 30 minutes ; little if any further 

 advance in 45 and 60 minutes, respectively. (Chart 

 D 453.) 



The reaction with sodium salicylate begins imme- 

 diately. Complete gelatinization occurs in about 10 per 

 cent of the entire number of grains and 16 per cent of 

 the total starch in 5 minutes; in about 37 per cent of 

 the grains and 47 per cent of the total starch in 10 min- 

 utes ; in about 60 per cent of the grains and 70 per cent 

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

 of the grains and 99 per cent of the total starch in 30 

 minutes. ( Chart D 454.) 



This was repeated because it is usually more rapid 

 than 1. persica var. purpurea, but the results were about 

 the same as the above. 



The hilum is more distinct than in 7. persica var. 

 purpurea, but a bubble is not so often formed there, 

 and when it appears it is very small. The lamellae are 

 more distinct than in I. persica var. purpurea. The 

 grains become more refractive in appearance after the 

 addition of the reagent, and the first part to show this 

 is the margin around which is formed a rather narrow 

 refractive band which is more refractive than in I. per- 

 sica var. purpurea. Gelatinization begins at the distal 

 margin, but usually not at separate points which have 

 become cracked first, as in /. persica var. purpurea, but 

 all along the border. In more grains than in /. persica 

 var. purpurea, 2 longitudinal refractive fissures extend 

 upward from the distal margin toward the hilum, and 

 the starch included between them is gelatinized some- 

 what more rapidly than the marginal portion, other- 

 wise the progress of gelatinization is much smoother and 

 is unaccompanied by any of the longitudinal fissuring 

 noted in /. persica var. purpurea. A canal is not seen to 

 form from the hilum to the gelatinized portion of the 

 grain as in I. persica var. purpurea, and the bubble 

 swells somewhat but quickly disappears. The gelatinized 

 grains are much swollen and have thicker capsules, but 

 are usually as much distorted as in 7. persica var. 

 purpurea. 



The reaction with calcium nitrate begins immedi- 

 ately. Complete gelatinization occurs in about 9 per cent 



