BEGONIA. 



703 



tion, the grain-residues all color a light to moderate 

 indigo at their proximal ends; the capsules a deep violet; 

 and the solution a very deep indigo. 



Aniline Reactions. 



With gentian violet the grains all color lightly at 

 once, and in 30 minutes they are light to moderately 

 colored (value 40). A majority of the grains are colored 

 moderately, a moderate minority lightly, and a few 

 deeply. 



With safranin the grains all color lightly at once, and 

 in 30 minutes they are moderate to deeply colored (value 

 60). More of the grains are deeply colored than in gen- 

 tian violet, and very few are lightly colored. 



Temperature Reactions. 

 The temperature of gelatinization of the majority 

 of the grains is 00° to 61° C, and of all 62° to 64° C, 

 mean 63° C. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins imme- 

 diately. Complete gelatinization occurs in about 61 per 

 cent of the entire number of grains and 70 per cent of 

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

 grains and 96 per cent of the total starch in 10 minutes. 

 (Chart D527.) 



The hilum becomes rather indistinct, unattended by 

 the formation of a bubble in any of the grains. The 

 lamellae are not visible. The grains become somewhat 

 more refractive after the addition of the reagent, and the 

 first part of the grain to show this change is a rather 

 narrow band of material at the margin. Gelatinization 

 begins at the distal margin and from this point proceeds 

 smoothly toward the margin. In some grains it is pre- 

 ceded by a pitted appearance of the ungelatinized mater- 

 ial, and in others not. It usually proceeds more rapidly 

 along the margin than in the interior of the grain until 

 the margin is reached; at this point in the reaction a 

 bubble sometimes develops and swells, largely unaccom- 

 panied by swelling of the hilum, then shrinks and dis- 

 appears. The starch at the proximal margin is next gela- 

 tinized and last the material immediately surrounding 

 the hilum, and this is often split into 2 or 3 pieces which 

 are widely separated and gelatinize independently of one 

 another. The gelatinized grains are somewhat swollen, 

 have thick capsules, and are usually considerably dis- 

 torted but still retain some resemblance to the form of 

 an untreated grain. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 37 per cent of 

 the entire number of grains and 77 per cent of the total 

 starch in 5 minutes ; in about 44 per cent of the grains 

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

 about 80 per cent of the grains and 99 per cent of the 

 total starch in 30 minutes. (Chart D 528.) (See page 

 697.) 



The hilum becomes distinct, unaccompanied by the 

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

 are moderately distinct. Gelatinization begins at the 

 hilum which swells rapidly toward the proximal end. 

 Two fissures extend from either side of the hilum three- 

 fourths of the distance to the distal margin. The starch 

 comprehended between these fissures at first merely 

 grows smaller in amount, and then as the grain swells it 



is fissured by irregular slanting fissures, beginning in 

 the portion near the hilum, which divide it into coarse 

 irregular granules. Before this process is tar advanced 

 the proximal end is dissolved, but solution of the grain 

 does not advance far until the greater part of the ill tal 

 granular portion is gelatinized and only a refractive 

 residue is left. In the meantime the outer Lamellated 

 layer is partially separated from the inner refractive 

 granular residue of the grain, and the two are dissolved 

 separately. 



The reaction with pijrogallic acid begins immediately. 

 Complete gelatinization occurs in less than 0.5 per cent 

 of the entire number of grains and 22 per cent of the total 

 starch in 5 minutes; in about 4 per cent of the grains 

 and 76 per cent of the total starch in 15 minutes ; in about 

 40 per cent of the grains and 92 per cent of the total 

 starch in 30 minutes; in about 64 per cent of the grains 

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

 about 66 per cent of the grains and 97 per cent of the 

 total starch in 60 minutes. (Charts D 529 and D 530.) 



The hilum becomes distinct, unattended by the for- 

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

 are distinct in a great majority of the grains, but in some 

 are not. Gelatinization begins at the hilum which en- 

 larges slowly. The starch just distal to the hilum 

 becomes indistinctly fissured, and refractive in appear- 

 ance, and all the distal material slowly grows smaller in 

 amount, finally forming a refractive granular mass at 

 the distal end. The starch at the proximal and distal 

 margin and sides forms a thick, very refractive band 

 which slowly becomes thinner and more nearly trans- 

 parent until it is gelatinized and only the capsule re- 

 mains. The granular mass at the distal margin is grad- 

 ually gelatinized at the same time, with some distortion of 

 the capsule at this point. This mass is not seen in all 

 the grains, but only in a rather small majority; in the 

 others only an added thickness of the marginal band at 

 the distal end is to be noted, and in such grains the 

 capsule is not distorted at the distal end. 



The gelatinized grains are moderately swollen, have 

 thick capsules, and are not greatly distorted, but more 

 in some grains than in others. (See note, page 698.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 90 per cent of 

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

 starch in 15 seconds; in more than 99 per cent of the 

 grains and total starch in 30 seconds. (Chart D 531.) 



The hilum becomes distinct in all the grains, attended 

 by the formation of a bubble in a majority of them. 

 The lamellae are moderately distinct. Gelatinization 

 begins at the hilum which swells rapidly, more rapidly 

 toward the proximal than toward the distal end. Two 

 indistinct fissures extend from either side of the hilum 

 nearly to the distal margin and the part of the grain 

 between them is indistinctly and irregularly fissured. 

 The bubble swells first, then shrinks, and finally dis- 

 appears, and a permanent invagination of one side of 

 the grain occurs at the same time. The distal portion is 

 rapidly gelatinized, leaving a small refractive granular 

 residue at the distal end, which, as the refractive homo- 

 geneous-looking band at the margin grows gradually 

 thinner and more nearly transparent, more or less slowly 

 gelatinizes, with considerable distortion of the capsules at 



