710 



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



are all colored a light to moderate indigo; the capsules 

 a moderate violet, and the solution a very deep indigo. 



Comparison of the iodine reactions between B. soco- 

 trana and B. double white shows : 



With 0.25 per cent Lugol's solution the grains all 

 color a light to moderate violet tinged with blue (value 

 30), 5 units more than in B. double white. With 0.125 

 per cent Lugol's solution the grains all color a very light 

 violet, more than in B. double white. After heating in 

 water until the grains are all gelatinized and then treating 

 with a 2 per cent Lugol's solution the gelatinized grains 

 all color more and the solution less than in B. double 

 white. If the preparation is boiled for 2 minutes and 

 then treated with an excess of a 2 per cent Lugol's 

 solution the grain-residues are all colored more, the 

 capsules a deeper violet, and the solution the same as in 

 B. double white. 



ANILINE REACTIONS. 



With gentian violet the grains all color very lightly 

 at once, and in 30 minutes they are lightly colored (value 

 30 ) . Most of the grains are colored lightly, a few very 

 lightly, and a few moderately colored. 



With safranin the grains all color very lightly at 

 once, and in 30 minutes they are lightly to moderately 

 colored (value 40), 10 units more than with gentian 

 violet. Most of the grains are colored lightly to moder- 

 ately, some lightly, and a very few deeply. 



Comparison of the aniline reactions between B. soco- 

 Irana and B. double white shows: 



With gentian violet the grains are light to moder- 

 ately colored (value 35), 5 units more than B. double 

 while. There are a few grains which are deeply colored. 



With safranin the grains are moderately colored 

 (value 55), 15 units more than with B. double iciiite. 

 More grains are colored deeply to moderately deeply than 

 in that starch. 



TEMPERATURE REACTIONS. 



The temperature of gelatinization of the majority of 

 the grains is 60 to 61.5 C., and of all 65 to 66.5 C., 

 the mean is 65.75 C. 



Comparison of the temperature reactions between B. 

 socotrana and B. double white shows : 



The temperature of gelatinization of all the grains 

 of B. socotrana is 81 to 81.8 C., mean 81.4 C., which 

 is 15.65 C. more than that of B. double white. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins imme- 

 diately. Complete gelatinization occurs in about 76 per 

 cent of the entire number of grains and 83 per cent of 

 the total starch in 5 minutes; in about 99 per cent of 

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

 in 10 minutes. (Chart D 533.) 



The hilum becomes rather indistinct in all the grains, 

 unattended by the formation of a bubble in any. The 

 lamella; are not visible. The grain becomes more refrac- 

 tive after the addition of the reagent, and the first part 

 of the grain to show this is a rather narrow band at the 

 margin which, however, does not become very refrac- 

 tive. Gelatinization begins at the distal margin and 

 proceeds rather irregularly to the hilum, preceded by 

 short cracks which invade the ungelatinized starch just 

 before gelatinization. It usually proceeds more rapidly 

 along the margin than in the interior of the grain, 



and the proximal margin is gelatinized before the starch 

 immediately around the hilum, which is, however, not 

 split when the hilum swells, but gelatinizes rapidly as 

 one piece. The gelatinized grains are much swollen, 

 have rather thick capsules, and are much distorted. 



Comparison of the chloral-hydrate reactions between 

 B. socotrana and B. double white shows: 



The hilum and lamellae are both invisible. Gela- 

 tinization in the majority of the grains begins at the 

 distal end and from there proceeds to the hilum and 

 proximal end. In a moderate minority the proximal 

 end is gelatinized soon after the distal end, and the most 

 resistant part of the grain is midway between the hilum 

 and the distal end. This method is not seen in B. double 

 white. In the first method the differences noted are 

 that gelatinization proceeds smoothly without any. pre- 

 liminary cracking of the ungelatinized starch as in 

 B. double white, and that the portion at the proximal 

 margin is the last to be gelatinized instead of that 

 immediately surrounding the hilum. The gelatinized 

 grains are as much swollen, and as much distorted, as in 

 B. double white but the capsules are rather thin instead 

 of thick. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 75 per cent of 

 the entire number of grains and 97 per cent of the total 

 starch in 5 minutes ; in about 86 per cent of the grains 

 and 99 per cent of the total starch in 15 minutes. (Chart 

 D 534.) (See pages 697 and 705.) 



The hilum becomes distinct, unattended by the for- 

 mation of a bubble in any of the grains. The lamellae 

 are distinct in some grains and not visible in others. 

 Gelatinization begins at the hilum which swells much 

 more rapidly toward the proximal end than toward the 

 distal end. Two fissures are formed which extend from 

 either side of the hilum one-half to three-fourths of 

 the distance between the hilum and the margin. The 

 starch comprehended between these fissures becomes in- 

 distinctly granular and is gelatinized very rapidly, leav- 

 ing in some grains a small refractive mass at the distal 

 end, but in the majority only a marginal band which 

 is broader at the distal than at the proximal end. The 

 capsule is then dissolved at the proximal end and solu- 

 tion proceeds toward the distal which is the last to be 

 dissolved. In some grains there is a separation of the 

 marginal band into 2 layers which dissolve independently. 



Comparison of the chromic-acid reactions between 

 B. socotrana and B. double white shows: 



The hilum and lamella; are somewhat more distinct 

 than in B. double white. Gelatinization begins at the 

 hilum which swells slightly, but not so rapidly as in B. 

 double white 'nor so much toward the proximal end. 

 The other differences noted are that the starch com- 

 prehended between the 2 fissures from the hilum is formed 

 into an inner granular mass which is easily differentiated 

 from the outer layer. This outer marginal layer is 

 finally dissolved at one corner of the distal margin, and 

 separated from the inner granular portion which may 

 be dissolved first or last. 



The reaction with pyrogallic acid begins immediately. 

 Complete gelatinization occurs in about 42 per cent of 

 the grains and 84 per cent of the total starch in 5 

 minutes ; in about 62 per cent of the grains and 95 per 

 cent of the total starch in 15 minutes; in about 73 per 



