BEGONIA. 



705 



Most of the grains are colored moderately lightly, a few 

 lightly, and a very few deeply. 



With safranin the grains all color lightly at once, and 

 in 30 minutes they are moderately colored (value 55), 5 

 units less than in B. double light rose; few of the grains 

 are colored lightly, the majority moderately, and a mod- 

 erate number deeply. 



Temperature Reactions. 

 The temperature of gelatinization of the majority 

 of the grains is 79° to 80° C, and of all 81° to 81.8° C, 

 mean 81.4° C. The mean is 18.4° higher than in B. 

 double light rose. 



Effects of Various Reaqents. 



The reaction with chloral hydrate begins immediately. 

 Complete gelatinization occurs in about 25 per cent of 

 the entire number of grains and 38 per cent of the total 

 starch in 5 minutes; in about 72 per cent of the grains 

 and 79 per cent of the total starch in 10 minutes; in 

 the entire number of grains and 38 per cent of the total 

 starch in 15 minutes. (Charts D 505 and D 527.) 



The hilum is invisible and bubble formation is not 

 noted in any of the grains. The lamellse also are in- 

 visible. The grains become 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 starch at the 

 margin which becomes more refractive than in B. double 

 light rose. Gelatinization begins at 1 or 2 discrete points 

 on the distal margin which are first cracked, and then fol- 

 lows two methods : In the first, which is seen in a small 

 majority, the process spreads from these points along the 

 whole distal margin, and thence toward the hilum, never 

 preceded by a pitted appearance of the ungelatinized 

 starch as in B. double light rose. When the hilum is 

 reached it swells, and the proximal starch is rapidly 

 gelatinized. In the second method, the proximal end 

 is gelatinized soon after the distal end, and gelatiniza- 

 tion proceeds more rapidly from the proximal than from 

 the distal end, and more rapidly along the margin than 

 in the interior, a central core of the grain being left 

 projecting as a cone into the surrounding gelatinized 

 starch. Finally this also is gelatinized. The gelatinized 

 grains are more swollen, have rather thin instead of 

 thick capsules, and are much more distorted, than in 

 B. double light rose. 



The reaction with chromic acid begins in rare grains 

 in 1 minute. Complete gelatinization occurs in less than 

 0.5 per cent of the entire number of grains and total 

 starch in 5 minutes; in less than 0.5 per cent of the 

 grains and 2 per cent of the total starch in 15 minutes; 

 in about 5 per cent of the grains and 60 per cent of the 

 total starch in 30 minutes; in about 10 per cent of the 

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

 in about 16 per cent of the grains and 92 per cent of 

 the total starch in 60 minutes. (Chart D 506.) 



Note.— The time-reactions with B. socotrana are much 

 glower than those of other specimens, as has been stated. The 

 margin of the grain remains very resistant throughout the 

 experiment, but at about 30 minutes much of the grain becomes 

 gelatinized and the process progresses quite rapidly until the 

 end of the reaction. This will be more fully described in the 

 notes on the qualitativve reactions. 



A portion of the margin of many of the grains of all 

 species is much more resistant than most of the grain, hence 



the percentage of gelatinization of the grains is much lower 

 than that of the total starch. The experiment lias been con- 

 sidered as complete when the total has reached 95 per cent 



or more. (See note, page (ill 7.) 



The hilum becomes as distinct as in B. double light 

 rose and the laniellte more distinct than in that starch. 

 Gelatinization begins at the hilum which swells slightly. 

 Two fissures which are continued as furrows extend from 

 either side of the hilum three-fourths of the distance 

 to the distal end, and 2 rows of slanting fissures are 

 quickly formed in the material just distal to the hilum. 

 The hilum swells very little and apparently no more 

 rapidly toward the proximal than toward the distal end. 

 The grain remains in this way without further change, 

 except that it grows more refractive, and is gradually 

 divided into an outer, homogeneous-looking layer and an 

 inner fissured and granular mass. The outer layer is 

 dissolved at one corner of the distal end, and in some 

 grains splits away from the inner granular portion which 

 is sometimes the last to be dissolved, but often is dissolved 

 first. 



The reaction with pyrogallic acid begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains and 

 total starch in 5 minutes; very little effect beyond a slight 

 swelling of the hilum occurs in 15, 30, 45, and 60 min- 

 utes. (Chart D 507.) 



The hilum is as distinct as in B. double light rose, 

 and the lamella are more distinct than in that starch. 

 Gelatinization begins at the hilum which enlarges some- 

 what. Two short fissures, which are not seen in B. double 

 light rose, appear extending from either side of the hilum 

 nearly half the distance to the distal margin. The 

 starch just distal to the hilum and comprehended between 

 these 2 fissures is divided by a double row of slanting 

 fissures which become more distinct as the grain swells 

 somewhat. Finally this part of the grain is gelatinized, 

 leaving a refractive granular residue at the distal end. 

 The starch at the proximal and distal margins and sides 

 forms a thick, refractive, lamellated, marginal band. No 

 further change within an hour except an increased re- 

 fractivity of the whole grain. (See note, page 698.) 



The reaction with nitric acid begins in 30 seconds. 

 Complete gelatinization occurs in less than 0.5 per cent 

 of the entire number of grains and 27 per cent of the 

 total starch in 5 minutes; in about 20 per cent of the 

 grains and 80 per cent of the total starch in 15 minutes; 

 in about 32 per cent of the grains and 88 per cent of the 

 total starch in 30 minutes ; in about 48 per cent of the 

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

 little if any further advance in 60 minutes. (Charts 

 D 509 and D 531.) 



The hilum becomes very distinct in all the grains, 

 and unlike in B. double light rose is unattended by the 

 formation of a bubble in any of the grains. Gelatiniza- 

 tion begins at the hilum which swells somewhat more 

 toward the proximal than toward the distal end, and 2 

 fissures form, which extend from either side of the hilum 

 nearly to the distal margin. The starch comprehended 

 between these 2 fissures is first divided rather indistinctly 

 by 2 rows of slanting fissures which become more and 

 more distinct, and this starch is slowly gelatinized, leav- 

 ing small pointed protuberances of refractive material 

 projecting from the sides into the center of the swelling 



