482 



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



which not all can be distinguished, a pure violet; and 

 the solution a deep indigo-blue. 



ANILINE REACTIONS. 



With gentian violet the grains stain very lightly at 

 once, and in half an hour they are light to moderately 

 colored (value 40). Some of the grains are more altered 

 than others, and many of the individual grains are more 

 stained at the distal end than elsewhere. 



With safranin the grains stain very lightly at once, 

 and in half an hour they are moderately colored (value 

 50). Some of the grains are more affected than others, 

 and many of the individual grains are more stained at the 

 distal end than elsewhere. 



TEMPERATURE REACTIONS. 



The majority of the grains are gelatinized at 64 

 to 65.5 C., and all at 70 to 71.5 C., mean 70.7 C. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 8 per cent of the entire number of grains and 12 

 per cent of the total starch in 5 minutes; in about 33 

 per cent of the grains and 37 per cent of the total starch 

 in 15 minutes; in about 62 per cent of the grains and 65 

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

 per cent of the grains and 67 per cent of the total starch 

 in 45 minutes ; in about 66 per cent of the grains and 72 

 per cent of the total starch in 60 minutes. (Chart D 190.) 



The liilum becomes distinct and a small bubble is 

 often formed there. The lamella?, also, are moderately 

 distinct, especially those which are less fine than the 

 majority. A broad, very refractive band (broader at the 

 distal end) is formed about the margins of the grains. 

 Gelatinization begins usually first at the distal end and 

 then, quickly, at the proximal end, or, less frequently, 

 at the proximal and then at the distal end, or, rarely, 

 at the distal end alone. Gelatinization progresses 

 smoothly, although with some invasion by fissures and 

 breaking off of fragments of the ungelatinized material 

 and separation and gelatinization serially of lamella 

 until the most resistant part, just distal to the hilum, is 

 reached; there the margin on either side is gelatinized 

 more rapidly than the inner portion which also is finally 

 gelatinized with considerable folding and invagination 

 of the capsule. In some of the less-resistant grains, 

 this resistant portion is divided by a refractive furrow 

 or fissure proceeding from the hilum which splits it 

 into two parts that gelatinize separately. The gela- 

 tinized grains are very large, very much distorted, espe- 

 cially at the distal end, and do not retain much of the 

 form of the untreated grain. 



The reaction with chromic acid begins in rare grains 

 immediately. Complete gelatinization occurs in much less 

 than 0.5 per cent of the entire number of grains and 

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

 0.5 per cent of the grains and 2 per cent of the total starch 

 in 15 minutes; in about 1 per cent of the grains and 36 

 per cent of the total starch in 30 minutes ; in about 46 

 per cent of the grains and 90 per cent of the total starch 

 in 45 minutes; in about 75 per cent of the grains and 95 

 per cent of the total starch in 60 minutes. (Chart D 191.) 



The reaction with pyrogallic acid begins in rare 

 grains immediately. Complete gelatinization occurs in 



about 0.5 per cent of the entire number of grains and 

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

 1 per cent of the grains and 2 per cent of the total starch 

 in 15 minutes; in about 2 per cent of the grains and 3 

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

 further advance in 45 and 60 minutes. (Chart D 192.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 19 per cent of 

 the entire number of grains and 62 per cent of the total 

 starch in 5 minutes ; in about 58 per cent of the grains 

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

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

 starch in 30 minutes ; in about 90 per cent of the grains 

 and 99 per cent of the total starch in 45 minutes; in about 

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

 of the total starch in 60 minutes. (Chart D 193.) 



The hilum becomes very distinct and the lamellae also 

 become very distinct and remain so, particularly at the 

 proximal end, throughout the greater part of the reaction. 

 Gelatinization begins at the hilum which enlarges some- 

 what. Two refractive fissures extend distally from either 

 side of the hilum, branching as they near the distal mar- 

 gin, and the material on either side along their courses 

 becomes transparent and then gelatinous while the whole 

 grain enlarges somewhat and becomes more nearly trans- 

 parent, but retains its structure. Next, regular cracks 

 invade the 2 or 3 marginal lamellee and divide them into 

 coarse granules. The hilum also begins to enlarge stead- 

 ily and the material immediately surrounding it, which 

 has become nearly transparent, is divided and sub- 

 divided by irregular fissures into rather fine granules. 

 In the meantime the rest of the grain excepting the 

 proximal end is completely gelatinized and the grain 

 swells considerably, and the granules around the hilum 

 are widely separated and scattered throughout the proxi- 

 mal end and often persist there after the rest of the 

 grain is gelatinized. The lamella at the proximal end 

 form a refractive, resistant band at the margin which is 

 invaded by cracks from the margin and then gelatinized 

 from the margin inward. The gelatinized grains are 

 thin-walled and somewhat distorted and do not show 

 much of the form of the untreated grain. 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 67 per cent of 

 the grains and 85 per cent of the total starch in 1 minute ; 

 in about 98 per cent of the grains and 99 per cent of the 

 total starch in 3 minutes ; in 100 per cent of the grains 

 and total starch in 5 minutes. (Chart D 194.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 63 per 

 cent of the entire number of grains and 90 per cent of 

 the total starch in 5 minutes; in about 91 per cent of 

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

 in 15 minutes. (Chart D 195.) 



The reaction with potassium hydroxide begins im- 

 mediately. Complete gelatinization occurs in about 88 

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

 of the total starch in 1 minute ; in about 95 per cent of 

 the grains and 99 per cent of the total starch in 3 min- 

 utes; in about 97 per cent of the grains and in more 

 than 99 per cent of the total starch in 5 minutes. ( Chart 

 D 196.) 



The reaction with potassium iodide begins imme- 

 diately. Complete gelatinization occurs in about 0.5 per 



