452 



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



The reaction with potassium iodide begins imme- 

 diately and a few grains are gelatinized in half a minute. 

 Complete gelatinization in about GS per cent of the en- 

 tire number of grains and 95 per cent of the total starch 

 in 5 minutes ; in about 93 per cent of the grains and 98 

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

 97 per cent of the grains and 99 per cent of the total 

 starch in 30 minutes. The proximal end and sides 

 nearby and scattered smaller grains are the most resist- 

 ant. At the end of 60 minutes nearly 1 per cent of 

 resistant starch remains. (Chart D 134.) 



A bubble appears at the hilum. The lamella? through 

 the mesial portion from the hilum to the distal margin 

 immediately become sharply defined and striated. A 

 refractive narrow band in which the lamella? gradually 

 become demonstrable remains at the proximal end and 

 sides. One or two plume-like fissures pass from the 

 hilum to the distal margin, and also to the proximal end 

 when an elongation is found at this region. The mesial 

 portion is quickly disorganized into irregularly arranged 

 fairly to quite refractive granules, the latter being located 

 in the area around the hilum. The lamellae near the 

 distal margin, and very gradually those in the band at the 

 proximal end and sides, are broken into linearly arranged 

 granules. A distal band in a few grains is quickly gela- 

 tinized, without the appearance of granules, gelatiniza- 

 tion being accompanied by much folding, imparting to 

 the grain the appearance of a ruffle at the end of an 

 ungelatinized part. Later the reaction involves the en- 

 tire grain. The gelatinized grains are swollen, yet most 

 of them are but very little distorted and accordingly. 

 bear some resemblance to the untreated grain. The 

 grains are rarely completely gelatinized. A narrow band 

 of either striated and sharply differentiated lamella? or 

 linearly arranged granules usually remains at the proxi- 

 mal end and sides, rarely around the entire margin. 



The reaction with potassium sulphocyanate begins 

 immediately. Several grains are fully gelatinized in half 

 a minute. Complete gelatinization occurs in about 75 

 per cent of the entire number of grains, including a few 

 scattered small grains, and 95 per cent of the total starch 

 in 3 minutes ; in about 85 per cent of the grains and 97 

 per cent of the total starch in 5 minutes; in about 92 

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

 in 10 minutes; and in about 97 per cent of the grains, and 

 in all but traces of starch in the proximal ends of some 

 of the grains in 30 minutes. (Chart D 135.) 



The hilum swells and a bubble forms which expands 

 very little and is then expelled. Much-branched fissures 

 pass from the hilum toward the distal margin, and gela- 

 tinization usually proceeds along their course. The 

 lamella? become very sharply defined and striated through 

 the mesial portion, especially when two longitudinal or 

 oblique fissures are formed. The starch is quickly 

 broken down with the appearance of fairly refractive 

 irregularly placed granules. The lamella? of a marginal 

 border in some grains become very sharply defined, and 

 is often followed by the gelatinization of this area pre- 

 vious to that of the rest of the grain. A narrow refractive 

 border at the proximal end and sides is the most resistant. 

 The lamella? forming this border become sharply defined 

 and striated, but they do not usually break into linearly 

 arranged granules previous to gelatinization. The gela- 



tinized grains are swollen and distorted, the distortion 

 being especially marked at the distal end. They are so 

 distorted as not to resemble the untreated grain. 



The reaction with potassium sulphide begins in a 

 few grains in 1 minute. Complete gelatinization occurs 

 in about 30 per cent of the entire number of grains and 

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

 36 per cent of the grains and 62 per cent of the total 

 starch in 15 minutes; in about 42 per cent of the grains 

 and 70 per cent of the total starch in 30 minutes; in 

 about the same percentage of grains and 78 per cent 

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

 cent of the grains and 81 per cent of the total starch in 

 60 minutes. (Chart D 136.) 



A bubble appears at the hilum and is generally ex- 

 pelled previous to much expansion. The lamella? be- 

 come very sharply defined and striated through the mesial 

 region from the hilum to the distal margin, a narrow 

 border at the proximal end and sides being very refrac- 

 tive and quite gradually becoming differentiated into 

 lamella?. One or two fissures are quickly formed which 

 extend from the hilum toward the distal margin, and also 

 toward the proximal end when protuberances occur at this 

 point. These fissures are much branched and plume- 

 like. When a distal narrow border is separated from the 

 main body of the grain by a prominent lamella, a separate 

 set of fissures may radiate from this lamella, through the 

 border to the distal margin. Gelatinization usually 

 spreads quickly through the mesial portion to the distal 

 margin, but it may begin either at the distal border 

 accompanied by distortion which imparts a ruffled ap- 

 pearance to this border, or when a protuberance is prom- 

 inent it may start at this point or quickly follow the 

 process in the mesial portion. In most grains, however, 

 a narrow band at the proximal end and sides is the most 

 resistant. The mesial portion is gelatinized sometimes 

 without the appearance of refractive granules, but fre- 

 quently fairly refractive granules appear in clusters along 

 the course of the fissures. The distal border is occasion- 

 ally gelatinized without the appearance of granules, but 

 often one to several rows of linear granules appear. 

 Sometimes a single row of granules may be seen at one 

 or more points in the mesial portion, the granulation re- 

 sulting from the disorganization of scattered and more 

 refractive lamella? that frequently occur in the grains of 

 this species. The gelatinized grains are much swollen 

 and considerably distorted, especially at the distal margin, 

 though the distortion is not so great in this reaction as 

 in many others. Occasionally a narrow striated band 

 remains at the proximal end. The gelatinized grains 

 are so distorted as not to resemble the untreated grain. 



The reaction with sodium hydroxide begins imme- 

 diately and within 1 minute many grains are wholly 

 gelatinized. Complete gelatinization occurs in about 64 

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

 of the total starch in 3 minutes; in about 80 per cent 

 of the grains and 97 per cent of the total starch in 5 

 minutes; and in about 98 per cent of the grains and 

 99 per cent of the total starch in 10 minutes. Only 

 traces of ungelatinized starch remain in rare grains at 

 the end of 15 minutes. (Chart D 137.) 



The reaction with sodium sulphide begins imme- 

 diately and a few grains are gelatinized in 1 minute. 



