620 



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



greases from these two points, preceded by small fissures 

 which invade the ungelatinized starch and separate off 

 small pieces which are then gelatinized. The last part 

 of the grain to be gelatinized is that just distal to the 

 hilum, and this is never split into two pieces, but is 

 slowly gelatinized, as a whole, in the same manner as the 

 rest of the grain. The gelatinized grains are much 

 swollen, have rather thin capsules, and are greatly dis- 

 torted ; they do not bear any resemblance to the form of 

 the untreated grain. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 46 per cent of 

 the entire number of grains and 85 per cent of the total 

 starch in 3 minutes; in about 61 per cent of the grains 

 and 89 per cent of the total starch in 5 minutes ; and in 

 about 94 per cent of the grains and 99 per cent of the 

 total starch in 15 minutes. (Chart D 368.) 



The hilum becomes distinct in all the grains, attended 

 by the formation of a bubble in a few. The lamella? are 

 distinct. Gelatinization begins at the hilum, which 

 swells more rapidly proximally than distally. Two fis- 

 sures extend from either side of the hilum about three- 

 fourths of the distance from the hilum to the distal 

 margin, and the starch included between them is broken 

 up into refractive irregular spicules by many distinct 

 and irregularly branching fissures. The deposit at the 

 proximal and distal margins and sides meanwhile forms 

 a refractive, homogeneous-looking band, which is thin- 

 ner at the proximal end than elsewhere. The inner 

 spicular portion is now gelatinized, causing the grain 

 to swell and leaving a residue of scattered refractive 

 granules which are especially numerous at the distal end. 

 The capsule and the marginal starch are dissolved at the 

 distal end, and a broad band showing traces of a lamellar 

 structure separates off from the inner granular part of 

 the grain. This is dissolved and then the rest of the 

 capsules, the inner granular part of the grain often being 

 the last to dissolve. 



The reaction with pyrogallic acid begins immediately. 

 Complete gelatinization occurs in about 11 per cent of the 

 entire number of grains and 78 per cent of the total 

 starch in 5 minutes; in about 67 per cent of the grains 

 and 95 per cent of the total starch in 15 minutes; and 

 in about 85 per cent of the grains and 98 per cent of the 

 total starch in 30 minutes. (Chart D 369.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 94 per cent of 

 the entire number of grains and 98 per cent of the total 

 starch in 15 seconds, and in more than 99 per cent of 

 the grains and total starch in 30 seconds. The rare scat- 

 tered grains ungelatinized in 30 seconds may resist gela- 

 tinization for 5 minutes or longer. 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 86 per cent of 

 the entire number of grains and 95 per cent of the total 

 starch in 30 seconds, and in more than 99 per cent of 

 the grains and total starch in 1 minute. 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 91 per 

 cent of the entire number of grains and 95 per cent of 

 the total starch in 15 seconds, and in 100 per cent of the 

 grains and total starch in 30 seconds. 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization occurs in more than 99 



per cent of the entire number of grains and total starch 

 in 10 seconds, and in 100 per cent of the grains and total 

 starch in 15 seconds. 



The hilum becomes distinct in all the grains, un- 

 attended by the formation of a bubble in any. The 

 lamellae are distinct. The hilum is slightly distinct, and 

 a fissure extends from either side one-half to three- 

 fourths of the distance from the hilum to the distal 

 margin. The portion included between these 2 fissures 

 is streaked with very fine, branching fissures which are 

 very numerous and become more and more distinct as 

 the grain swells. In some grains the portion imme- 

 diately distal to the hilum is divided into several divisions 

 by a double row of fissures which slant proximally from 

 the 2 original fissures extending from the hilum to the 

 longitudinal axis of the grain. These divisions are 

 quickly gelatinized and leave a residue of refractive 

 granules. The rest of the fissured distal starch gela- 

 tinizes comparatively slowly, the fissures becoming more 

 and more distinct. As the grain swells some of these 

 fissures open out, dividing the starch into irregular 

 pyramidal divisions and so forming a serrated inner 

 border to the distal margin. The divisions are each 

 fissured and may be divided into spicules. They remain 

 for some little time and are finally gelatinized with 

 much infolding and distortion of the capsule. The 

 granules remaining from the gelatinization of the upper 

 part of the starch distal to the hilum are also slowly 

 gelatinized. The portion at the proximal margin and 

 sides forms a rather thick, homogeneous-looking, refrac- 

 tive band which is slowly gelatinized. The gelatinized 

 grains are greatly swollen, have thick capsules, and are 

 very much distorted, particularly at the distal end, but 

 sometimes in all parts of the capsule. 



The reaction with potassium iodide begins imme- 

 diately. Complete gelatinization occurs in about 70 per 

 cent of the entire number of grains and 85 per cent of 

 the total starch in 30 seconds ; in about 95 per cent of the 

 grains and 99 per cent of the total starch in 1 minute; 

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

 starch in 3 minutes. Eare resistant grains remain un- 

 gelatinized for 5 minutes or longer. 



The reaction with potassium sulphocyanate begins 

 immediately. Complete gelatinization occurs in about 53 

 per cent of the entire number of grains and 73 per cent 

 of the total starch in 15 seconds; in about 75 per cent 

 of the grains and 95 per cent of the total starch in 30 

 seconds; and in about 99 per cent of the grains and 

 in more than 99 per cent of the total starch in 1 minute. 

 Very rare grains remain ungelatinized for 2 minutes. 



The reaction with potassium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 97 per 

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

 total starch in 15 seconds. Very rare grains may resist 

 gelatinization for 5 minutes or longer. 



The reaction with sodium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 79 per 

 cent of the entire number of grains and 94 per cent of 

 the total starch in 15 seconds, and in about 96 per cent 

 of the grains and 99 per cent of the total starch in 30 

 seconds. Eare resistant grains may remain ungelatinized 

 for 5 minutes or longer. 



The reaction with sodium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 71 per 



