68G 



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



Lugol's solution, the grain-residues become a very deep 

 blue, many with a reddish tint; most of the capsules color 

 a wine-red, with a few deep heliotrope ; and the solution 

 becomes a deep indigo-blue. 



Aniline Reactions. 



With gentian violet the grains stain lightly at once, 

 and in half an hour they are light to moderate (value 40) 

 in color. 



With safranin the grains color lightly at once, and 



in half an hour they are light to moderate (value 40) 



in color. 



Temperature Reactions. 



The majority of the grains are gelatinized at 73° 

 to 75° C, and all at 76° to 77.5° C, mean 76.7° C. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins imme- 

 diately. Complete gelatinization occurs in about 7 per 

 cent of the entire number of grains and 10 per cent of 

 the total starch in 5 minutes; in about 22 per cent of 

 the grains and 26 per cent of the total starch in 15 

 minutes ; in about 44 per cent of the grains and 48 per 

 cent of the total starch in 30 minutes; in about 52 per 

 cent of the grains and 60 per cent of the total starch in 

 45 minutes; in about 60 per cent of the grains and 63 

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

 D484.) 



The hilum becomes very prominent and a bubble is 

 frequently formed there No lamella? are visible A re- 

 fractive band is slowly formed around the margin of some 

 of the grains, but never appears in all. Gelatinization 

 begins at the distal end in those grains in which the 

 hilum is eccentric, in others at some point on the margin, 

 and in a few all around the margin. It is preceded in 

 every case by a deep pitting of the surface. As gela- 

 tinization progresses the ungelatinized starch is invaded 

 by fissures, and masses are broken off and then gelatinized, 

 finally the hilum is reached ; the bubble if present shrinks 

 and disappears, but the hilum itself is not observed to 

 swell, and the portion at the proximal end finally is 

 gelatinized. Because of the fact that the proximal starch 

 is the last to gelatinize we often find an apparent invag- 

 ination at the proximal end of the gelatinized grains, 

 otherwise though considerably enlarged they retain much 

 of their original form. About two-fifths of the total 

 number of grains are not gelatinized at the end of 1 hour. 



The reaction with chromic acid begins in a few 

 grains in half a minute. Complete gelatinization occurs 

 in about 1 per cent of the grains and 5 per cent of the 

 total starch in 5 minutes; in about 6 per cent of the 

 grains and 50 per cent of the total starch in 15 minutes ; 

 in about 50 per cent of the grains and 98 per cent of the 

 total starch in 30 minutes ; in about 65 per cent of the 

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

 in about 95 per cent of the grains and over 99 per cent of 

 the total starch in 60 minutes. (Chart D 485.) 



The reaction with pyrogallic acid begins immedi- 

 ately. Complete gelatinization occurs in about 4 per cent 

 of the entire number of grains and 13 per cent of the 

 total starch in 5 minutes; in about 28 per cent of the 

 grains and 54 per cent of the total starch in 15 minutes ; 

 in about 34 per cent of the grains and 78 per cent of 

 the total starch in 30 minutes; in about 43 per cent of the 



grains and 91 per cent of the total starch in 45 minutes; 

 in about 51 per cent of the grains and 96 per cent of the 

 total starch in 60 minutes. (Chart D 486.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 2 per cent of the 

 entire number of grains and 10 per cent of the total 

 starch in 5 minutes ; in about 14 per cent of the grains 

 and 25 per cent of the total starch in 15 minutes; in 

 about 30 per cent of the grains and 47 per cent of the 

 total starch in 30 minutes; very slight progress in 45 

 minutes; in about 33 per cent of the grains and 50 per 

 cent of the total starch in 60 minutes. (Chart D 487.) 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 90 per cent of 

 the entire number of grains and 99 per cent of the total 

 starch in 5 minutes; complete gelatinization of all grains 

 (100 per cent both of the grains and total starch) occurs 

 in 10 minutes. (Chart D 488.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 37 per 

 cent of the entire number of grains and 80 per cent of the 

 total starch in 5 minutes; in about 63 per cent of the 

 grains and 92 per cent of the total starch in 15 minutes; 

 in about 68 per cent of the grains and 95 per cent of 

 the total starch in 30 minutes; in about 82 per cent of 

 the grains and 97 per cent of the total starch in 45 min- 

 utes; in about 85 per cent of the grains and 99 per cent 

 of the total starch in 60 minutes. (Chart D 489.) 



The hilum becomes very distinct and two canals or 

 fissures are projected from the hilum to the distal corners 

 of the pressure facets. The lamellae are not visible. 

 Gelatinization is often preceded by a pitted appearance 

 of the surface at the margin, and occasionally over the 

 whole grain. Gelatinization begins at the hilum, and in 

 most of the grains (almost immediately afterwards) at 

 a point on the margin, or in those grains with pressure 

 facets at the corners of the pressure facets. The initial 

 enlargement of the hilum is followed by the appearance 

 of fine striae radiating to the margin in every direction, 

 except in the one segment between the hilum and the 

 point on the margin which is gelatinized — here all the 

 starch is gelatinized. The fine striae divide the substance 

 of the grain into spicules, and as gelatinization proceeds 

 granules are broken off the ends of these until the in- 

 terior of the grain is filled with fine granules. The 

 remainder of the starch forms a broad striated band 

 at the margin, around the inner border of this is a row 

 of rather coarse granules, these and the finer granules 

 in the interior of the grain are gelatinized and the 

 striated margin is broken up into coarse granules which 

 finally are also gelatinized. The capsule in the meantime 

 is sometimes, but not often, dissolved at several points, 

 and the separated pieces of the margin float off and are 

 gelatinized separately. The gelatinized grains which 

 remain intact are large and considerably distorted, but 

 retain some of the form of the untreated grain. 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 2 per 

 cent of the entire number of grains and 9 per cent of the 

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

 entire number of grains and 15 per cent of the total 

 starch in 15 minutes; in about 15 per cent of the entire 

 number of grains and 28 per cent of the total starch in 

 30 minutes; in about 20 per cent of the grains and 33 



