380 



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



become a deep purple, the mean is deep, the solution be- 

 comes a deep indigo-blue. If the preparation is boiled 

 for 2 minutes and then treated with an excess of 2 per 

 cent Lugol's solution most of the grain-residues color a 

 deep to very deep indigo-blue, but a few have a reddish 

 tint, only a few are colored very deep ; the capsules color 

 a light old-rose to deep heliotrope, mean moderate to 

 deep in color. The solution becomes a very deep indigo- 

 blue. 



ANILINE REACTIONS. 



With gentian r.iolet the grains stain very lightly to 

 lightly at once, and in half an hour they become moderate 

 with a few deep (value 55), also some unevenness in 

 color of the individual grains. 



With safranin the grains stain very lightly at once 

 and in half an hour they become moderate with a few 

 deep (value 55) in color. The same unevenness in color 

 of the individual grains is noted as when treated with 

 gentian violet. 



TEMPERATURE REACTIONS. 



The majority of the grains are gelatinized at 70 

 to 71 C., and in all but the distal end of rare grains 

 at 72.5 to 73 C., mean 72.75. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins at once in 

 a few grains. Complete gelatinization occurs in about 

 5 per cent of the entire number of grains and 12 per cent 

 of the total starch in 5 minutes ; in about 41 per cent of 

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

 minutes; in about 77 per cent of the grains and 85 

 per cent of the total starch in 30 minutes ; in about 84 

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

 in 45 minutes; in about 92 per cent of the grains and 

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

 D 1.) A bubble appears at the hilum which is quite ! 

 persistent and remains small until the approach of the 

 gelatinized area; it may then expand a little previous : 

 to expulsion. The lamellae do not become any more ; 

 distinct. A refractive border is found which envelops 

 the entire margin ; it broadens as the process continues, 

 but always remains wider at the distal margin. Gela- j 

 tinization usually starts at the distal margin but is i 

 quickly followed at the proximal end of most grains; | 

 the process is generally accompanied by considerable dis- 

 tention and distortion of the capsule. Irregular channels 

 may form previous to complete gelatinization in the 

 more resistant area of a few grains ; in such grains gela- 

 tinization may be completed in the less refractive area 

 before the process is finished in the more refractive bor- 

 der. The most resistant starch is generally found in a j 

 band just distal to the hilar region. The gelatinized 

 grains are much swollen and distorted, so that they do 

 not resemble the untreated grain. 



The reaction with chromic acid begins in a few grains 

 in half a minute. Complete gelatinization occurs in about 

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

 of the total starch in 5 minutes ; in about 15 per cent of 

 the grains and 70 per cent of the total starch in 15 j 

 minutes ; in about 50 per cent of the grains and 88 per ! 

 cent of the starch in 20 minutes ; in about 65 per cent of j 

 the grains and 95 per cent of the total starch in 25 min- 

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



cent of the total starch in 30 minutes; all are gelatinized 

 in 35 minutes. ( Chart D 2.) 



The reaction with pyrogallic acid begins in a few 

 grains in half a minute. Complete gelatinization occurs 

 in about 1 per cent of the entire number of grains and 

 5 per cent of the total starch in 5 minutes; in about 17 

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

 in 15 minutes; in about 35 per cent of the grains and 

 75 per cent of the total starch in 30 minutes ; in about 35 

 per cent of the grains and 85 per cent of the total starch 

 in 45 minutes; in about 35 per cent of the grains and 90 

 per cent of the total starch in 60 minutes. A small 

 area at the distal end is very resistant. (Chart D 3.) 



The reaction with nitric acid begins in all the grains 

 immediately. Complete gelatinization occurs in about 

 50 per cent of the grains and total starch in half a min- 

 ute ; in about 95 per cent of the grains and of the total 

 starch in 1 minute; in about 99 per cent of the grains 

 and total starch in 2 minutes; in about 99 per cent of 

 the grains and of the total starch in 3 minutes. Very 

 slight progress in 5, 10, and 15 minutes, but complete 

 gelatinization of all of the grains in 30 minutes. (Chart 

 D 4.) A bubble appears at the hilum which expands 

 considerably; in some grains it is very quickly expelled, 

 while in others it less rapidly disappears and moves dis- 

 talward through the mesial region. The lamellae become 

 more distinct, and a narrow refractive border is formed. 

 Gelatinization advances rapidly through the mesial re- 

 gion from the hilum to the distal margin ; a few lamellae 

 at the distal margin may become striated and disorgan- 

 ized into refractive granules previous to gelatinization. 

 Well-defined fissures do not usually appear during the 

 progress of the reaction. The most resistant area is 

 the narrow border at the distal margin. 



The gelatinized grains are swollen and slightly to 

 considerably distorted; the distortion is greater at the 

 distal margin and rarely a few refractive granules may 

 remain a short distance above the distal margin. 



The reaction with sulphuric acid begins immediately 

 in all of the grains, and many are completely gelatinized 

 in half a minute. Complete gelatinization occurs in 

 about 95 per cent of the grains and of the total starch 

 in 1 minute ; in about 98 per cent of the grains and of 

 the total starch in 1.25 minutes; and in all the grains 

 in 1.5 minutes. (Chart D 5.) 



The reaction with hydrochloric acid begins imme- 

 diately in all of the grains. Complete gelatinization 

 occurs in about 50 per cent of the grains and the total 

 starch in 15 seconds; in about 95 per cent of the grains 

 and total starch in 1 minute ; and in over 99 per cent of 

 the grains and total starch in 2 minutes. There is little 

 change in 5 minutes, but gelatinization is complete in 10 

 minutes. (Chart 6.) 



The reaction with potassium hydroxide is complete in 

 all of the grains in 15 seconds. (Chart D 7.) 



The reaction with potassium iodide begins immedi- 

 ately. Complete gelatinization occurs in about 22 per 

 cent of the grains and 89 per cent of the total starch in 

 5 minutes; in about 42 per cent of the grains and 96 

 per cent of the total starch in 15 minutes; in about 58 

 per cent of the grains and 98 per cent of the total starch 

 in 30 minutes; in about 69 per cent of the grains and 99 

 per cent of the total starch in 45 minutes; in about 73 



