BEGONIA. 



715 



With gentian violet the grains are lightly to moder- 

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

 deep rose. There is as much variation in depth of color 

 in the different grains as in that starch. 



With safranin the grains are moderately colored 

 (value 55), 5 units less than in B. double deep rose. 

 There is the same amount of variation in depth of color 

 in the different grains as in that starch. 



TEMPERATURE REACTIONS. 



The temperature of gelatinization of the majority 

 of the grains is 64 to 65.5 C., and of all 67 to 68.8 

 C., mean 67.8 C. 



Comparison of the temperature reactions between 

 B. socotrana and B. double deep rose shows : 



The temperature of gelatinization is 81 to 81.8 C., 

 mean 81.4 C., which is 13.6 C. higher than that of B. 

 double deep rose. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with ch loral hydrate begins immediately. 

 Complete gelatinization occurs in about 96 per cent of 

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

 starch in 5 minutes. ( Chart D 539.) 



The hilum becomes moderately distinct in all the 

 grains, attended by the formation of a bubble in a 

 majority of the grains. The lamella? are never 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 around the 

 margin which is quite refractive. Gelatinization begins 

 first at discrete points at the distal end, and in the major- 

 ity of the grains immediately afterwards at the proximal 

 end. Gelatinization advances smoothly from these two 

 points and the last portion of the grain to be gelatinized 

 is that immediately distal to the hilum. This is usually 

 split into two parts which gelatinize independently of 

 one another. In a minority of the grains gelatinization 

 occurs at the distal end only and proceeds smoothly from 

 this point to the proximal end which is the last part of the 

 grain to be gelatinized. The gelatinized grains are 

 moderately swollen, have rather thick capsules, and are 

 considerably distorted. 



Comparison of the chloral-hydrate reactions between 

 B. socotrana and B. double deep rose shows : 



The hilum and lamellae are both invisible and a bub- 

 ble formation is not formed at the hilum, as in a 

 majority of the grains of B. double deep rose. The 

 grains become more refractive after the addition of the 

 reagent, and the first part to show this change is a rather 

 narrow band of starch at the margin which is not so 

 refractive as in B. double deep rose. Gelatinization be- 

 gins at discrete points on the distal end of the grains and 

 in a small majority of the grains proceeds exactly as 

 in a minority of B. double deep rose. In a large minor- 

 ity it progresses very much as in a majority of the grains 

 of B. double deep rose, the only difference noted being 

 that gelatinization advances more rapidly from the proxi- 

 mal than from the distal margin so that the last part of 

 the grain to be gelatinized is midway between the hilum 

 and the distal end, instead of just distal to the hilum; 

 and this part of the grain is never split into two pieces as 

 in B. double deep rose. The gelatinized grains are as 

 much swollen and as much distorted as in B. double deep 

 rose, but have thin instead of rather thick capsules. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 17 per cent of 

 the entire number of grains and 65 per cent of the total 

 starch in 5 minutes; in about 48 per cent of the grains 

 and 93 per cent of the total starch in 15 minutes; in 

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

 cent of the total starch in 30 minutes. (Chart D 540.) 

 (See pages 69 7 and 705.) 



The hilum becomes distinct in all the grains, unat- 

 tended by the formation of a bubble in any. The lamellae 

 are not visible. Gelatinization begins at the hilum, which 

 swells much more rapidly in the direction of the proxi- 

 mal than of the distal end. Two rather indistinct fis- 

 sures proceed from either side of the hilum nearly to 

 the distal margin. The starch comprehended between 

 these fissures is divided by fine irregular fissures and is 

 rapidly gelatinized, leaving a small refractive granular 

 residue at the distal end. In the meantime the portion 

 at the proximal and distal margins and sides forms a 

 marginal band which is broader at the distal margin 

 than elsewhere. It is at first homogeneous-looking, but 

 is later divided into lamellas. This is soon dissolved at 

 the proximal end and solution proceeds to the distal end, 

 which is the last to be dissolved. 



Comparison of the chromic-acid reactions between B. 

 socotrana and B. double deep rose shows : 



The hilum and lamellae are more distinct than in B. 

 double deep rose. Gelatinization begins at the hilum, 

 which swells somewhat but no more toward the proximal 

 than toward the distal end, and the progress of gelatiniza- 

 tion is different from B. double deep rose. The starch 

 which is comprehended between the 2 fissures from the 

 hilum, and which is immediately distal to the hilum, is 

 divided by a double row of slanting fissures. The grain- 

 residue gelatinizes without any further change except that 

 it becomes more refractive and is gradually divided into 

 an outer homogeneous layer and an inner granular mass. 

 The outer layer is dissolved at one corner and in some 

 grains splits away from the inner granular mass, which 

 may or may not be the last to be gelatinized. 



The reaction with pyrogallic acid begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 0.5 per cent of the entire number of grains and 25 per 

 cent of the total starch in 5 minutes; in about 32 per 

 cent of the grains and 77 per cent of the total starch 

 in 15 minutes ; in about 40 per cent of the grains and 88 

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

 52 per cent of the grains and 95 per cent of the total 

 starch in 45 minutes ; in about 56 per cent of the grains 

 and 96 per cent of the total starch in 60 minutes. (Charts 

 D 541 and D 542.) 



The hilum becomes distinct in all the grains, unat- 

 tended by the formation of a bubble in any. The lamella? 

 also gradually become distinct. Gelatinization begins 

 at the hilum, which swells somewhat. Two fissures are 

 seen to proceed from either side of the hilum practically 

 to the distal margin, and the starch which is compre- 

 hended between them and the hilum and the distal mar- 

 gin is indistinctly fissured and slowly gelatinized, leaving 

 a small refractive mass at the distal end which disappears 

 in time, the hilum meanwhile swelling more toward the 

 proximal than the distal end. The starch at the proxi- 

 mal end and sides forms at the margin a thick, refractive, 

 homogeneous band which slowly grows thinner and more 



