420 



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



from the hilum ; these fissures usually become very deep 

 and often much branched. The gelatinization of the 

 grains is varied in character, generally preceded by the 

 appearance of very refractive granules and often followed 

 by partial solution at the distal margin. In the grains 

 with a quite eccentric hilurn gelatinization starts at the 

 distal margin and advances towards the proximal end, 

 a narrow band at the proximal end and sides nearby 

 proving the most resistant part of the grain. When the 

 hilum is centric or but slightly eccentric, gelatinization is 

 almost simultaneous from both ends and then advances 

 towards the hilum, a narrow band for a short distance 

 at either side of the hilum proving the most resistant part 

 of the grain. Occasionally the reaction may start in the 

 border and extend around the grain previous to the gela- 

 tinization of the main body of the grain; this border 

 may either be considerably distorted, or the outermost 

 lamella may be broken down into linearly arranged gran- 

 ules bounding a much swollen but undistorted border. 

 In some grains the process proceeds along the course of 

 sharply defined fissures through the mesial region which 

 is quickly disorganized into a mass of very refractive 

 granules, a very refractive and profusely striated border 

 being the most resistant ; this border is finally disorgan- 

 ized at the distal margin previous to the disorganization 

 of the proximal end and sides nearby. 



The gelatinized grains are swollen and slightly to 

 much distorted so that they do not usually resemble the 

 form of the untreated grain. Many grains are but par- 

 tially gelatinized, a refractive band and also a mass of 

 refractive granules proving very resistant. A number 

 of grains are but little affected by the reagent at the end 

 of 60 minutes. 



The reaction w.ith sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 48 per cent of 

 the grains and 95 per cent of the total starch in 5 min- 

 utes; in over 99 per cent of both the grains and total 

 starch in 15 minutes; in 100 per cent of both the grains 

 and total starch in 30 minutes. (Chart D 68.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 10 per 

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

 the total starch in 5 minutes ; in about 38 per cent of the 

 grains and 75 per cent of the total starch in 15 minutes; 

 in about 50 per cent of the grains and 83 per cent of the 

 total starch in 30 minutes; in about 58 per cent of the 

 grains and 90 per cent of the total starch in 45 minutes ; 

 in about 60 per cent of the grains and 92 per cent of the 

 total starch in 60 minutes. (Chart D 69.) 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinizatiou occurs in about 13 per 

 cent of the entire number of grains and 16 per cent of 

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

 grains and 67 per cent of the total starch in 15 minutes; 

 in about 60 per cent of the grains and 72 per cent of the 

 total starch in 30 minutes; in about 61 per cent of the 

 grains and 81 per cent of the total starch in 45 minutes; 

 in about 67 per cent of the grains and 83 per cent of the 

 total starch in 60 minutes. (Chart D 70.) 



The reaction with potassium iodide 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 1 per cent of the total starch in 5 minutes ; in about 

 4 per cent of the grains and 12 per cent of the total 



starch in 15 minutes ; in about 14 per cent of the grains 

 and 29 per cent of the total starch in 30 minutes; in 

 about 26 per cent of the grains and 38 per cent of the 

 total starch in 45 minutes ; in about the same percentage 

 of the grains and 45 per cent of the total starch in 60 

 minutes. (Chart D 71.) 



The hilum swells slightly but a bubble is not formed 

 and if fissures are located at this region in the untreated 

 grain they become enlarged and more refractive. The 

 entire grain grows more refractive but in some grains 

 the lamellae appear more distinct, especially one which 

 forms a line of demarcation between the main body of 

 the grain and a border of slightly greater refractivity 

 than the main body of the grain. The fissures at the 

 hilum become more prominent and numerous branches 

 may proceed from them; 1 or 2 much-branched fissures 

 may proceed distalwards from the hilum, and sometimes 

 delicate fissures may radiate from the entire margin of 

 the hilum. The gelatinization of the grains is varied in 

 character. In the most quickly gelatinized grains, the 

 reaction advances from the hilum distalwards through 

 the mesial region; the lamella along this path are dis- 

 organized into a mass of refractive granules until a nar- 

 row, deeply striated band of starch is reached ; this band 

 being disorganized into linearly arranged very resistant 

 refractive granules, and these granules are located either 

 directly at the margin or just within a gelatinized border. 

 In some grains this band of granules becomes gelatinized, 

 those at the proximal end and sides nearby proving the 

 most resistant; in others this band may be broken into 

 small refractive segments followed by a dissolution of 

 the capsule at several points and a slitting of the grain. 

 Gelatinization of the grain is sometimes preceded by a 

 deeply pitted condition followed by the appearance of 

 numerous fissures and the rapid disorganization of the 

 lamellse into irregularly massed refractive granules. In 

 grains with a quite eccentric hilum the reaction usually 

 begins at the distal margin and advances towards the 

 proximal end, while in grains with centric or slightly 

 eccentric hilum the process may start almost simul- 

 taneously at both ends and advance towards the hilum. 



The gelatinized grains are swollen and slightly to 

 considerably distorted, so that they do not usually resem- 

 ble the untreated grain. Eefractive granules in other- 

 wise gelatinized grains are often present, and many 

 grains are but little affected at the end of 60 minutes 

 beyond the swelling of the hilum. 



The reaction with potassium sulphocyanate begins in 

 a few grains in half a minute. Complete gelatinization 

 occurs in about 7 per cent of the entire number of grains 

 and 11 per cent of the total starch in 5 minutes; in about 

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

 starch in 15 minutes ; in about 50 per cent of the grains 

 and 68 per cent of the total starch in 30 minutes; in 

 about 58 per cent of the grains and 75 per cent of the 

 total starch in 45 minutes; in about 63 per cent of the 

 grains and 84 per cent of the total starch in 60 minutes. 

 (Chart D 72.) 



The hilum enlarges slightly and is very distinct, but 

 no bubble is formed there, and, if the hilum is fissured 

 in the untreated grain, the fissures become enlarged. In 

 many of the grains, the lamellae become at first gradually 

 more distinct, and later are obscured by stria? radiating 

 from the hilum. Fissures if not already present at the 



