486 



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



less than 0.5 per cent of the entire number of grains and 

 total starch in 5 minutes; slight advance in 15 and 30 

 minutes; in about 0.5 per cent of the entire number of 

 grains and 1 per cent of the total starch in 45 minutes ; 

 little if any further advance in 60 minutes. (Chart 

 D 192.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 16 per cent of 

 the entire number of grains and 88 per cent of the total 

 starch in 5 minutes ; in about 77 per cent of the grains and 

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

 9-4 per cent of the grains and 99 per cent of the total 

 starch in 30 minutes. (Chart D 193.) The hilum and 

 lamellae are not so distinct as in N. crispa, and the lamella; 

 at the distal end while differing from those of the grains 

 of N. crispa remain distinct longer than at the proximal 

 end. Gelatinization as in N. crispa begins at the hilum, 

 but in these grains the proximal end is usually less re- 

 sistant than the distal end, and when the hilum and the 

 grain enlarge it is first at the proximal end and later 

 at the distal end. There are few if any granules formed 

 of the mass immediately surrounding the hilum; and 

 the marginal band which extends completely around the 

 grain, instead of being only at the proximal end as in 

 N. crispa, is not invaded by cracks and so divided into 

 granules as in those grains, but remains as a homo- 

 geneous-looking band which becomes progressively thin- 

 ner and more nearly transparent and finally is gelati- 

 nized, leaving only the thin capsule. The gelatinized 

 grains are large and thin-walled but not so distinct as in 

 N. crispa, and retain more of the form of the untreated 

 grain. 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 77 per cent of 

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

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

 and more than 99 per cent of the total starch in 3 min- 

 utes ; in about 99 per cent of the grains and more than 

 99 per cent of the total starch in 5 minutes. (Chart 

 D 194.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 55 per 

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

 the total starch in 5 minutes; in about 90 per cent 

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

 starch in 15 minutes. (Chart D 195.) 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 95 per 

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

 the total starch in 1 minute ; in about 98 per cent of the 

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

 in 5 minutes, very little change in 15 minutes. (Chart 

 D196.) 



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 

 total starch in 5 minutes; in less than 0.5 per cent of 

 the grains and 1 per cent of the total starch in 15 min- 

 utes; in less than 0.5 per cent of the grains and 2 per 

 cent of the total starch in 30 minutes; in about 0.5 per 

 cent of the grains and 3 per cent of the total starch in 

 45 minutes ; in about 2 per cent of the grains and 8 per 

 rent of the total starch in 60 minutes. (Chart D 197.) 

 The hilum and lamellae are not so distinct as in N. crispa, 



and gelatinization as in N. crispa begins at the hilum, 

 which enlarges slowly at the same time that 2 refractive 

 fissures extend distally. The process is much the same 

 as that described under N. crispa, except that fissuration 

 and granulation of the starch immediately surrounding 

 the hilum are much more common in these grains than 

 in N. crispa and the material included between the 2 

 refractive fissures already mentioned is often divided 

 into distinct, rather coarse granules by branches from 

 the fissures. No grains are noted in which one of the 

 fissures turn to one side rather than to the distal margin 

 such as are noted in N. crispa. The gelatinized grains 

 are large and somewhat more distorted than those of N. 

 crispa. 



The reaction with potassium sidphocyanate begins in 

 a few grains immediately. Complete gelatinization 

 occurs in about 1 per cent of the entire number of 

 grains and 3 per cent of the total starch in 5 minutes; 

 in about 2 per cent of the grains and 10 per cent of the 

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

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

 in about 18 per cent of the grains and 40 per cent of the 

 total starch in 45 minutes; in about 22 per cent of 

 the grains and 55 per cent of the total starch in .60 

 minutes. (Chart D 198.) The hilum is distinct, but 

 not as distinct as in N. crispa, and the lamella? are 

 moderately distinct and remain so during the greater 

 part of the reaction, but are not so distinct as in N. crispa. 

 Before gelatinization begins two fissures in the interior 

 of the grain are seen to extend from the hilum nearly 

 to the distal margin as in N. crispa, but the material 

 between them does not become lighter and more refractive 

 in appearance as in N. crispa. Gelatinization as in N. 

 crispa begins at the hilum, but the proximal starch is 

 usually the first to be gelatinized rather than the distal 

 material as in N. crispa. After the hilum has enlarged 

 in the direction of the proximal end and most of the 

 proximal material is gelatinized, the distal portion be- 

 comes rather refractive and assumes a pitted appearance 

 and then gelatinizes from the hilum distally. The last 

 part of the grain to be gelatinized is the portion on either 

 side of the distal margin. The gelatinized grains are 

 moderately large and as distorted as those of N. crispa. 



The reaction with potassium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 21 per 

 cent of the entire number of grains and 62 per cent of 

 the total starch in 5 minutes; in about 69 per cent of 

 the grains and 91 per cent of the total starch in 15 

 minutes ; in about 81 per cent of the grains and 95 per 

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

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

 45 minutes ; little if any further advance in 60 minutes. 

 (Chart D 199.) The hilum and lamellae are less distinct 

 than in N. crispa. Gelatinization, as in N. crispa, begins 

 at the hilum. As the proximal end is usually the least 

 resistant part of the grain it differs in this respect from 

 those of N. crispa. The hilum and grain both swell 

 in this direction first, and the portion here is gelatinized 

 comparatively quickly without the formation of granules. 

 Then the distal material, which has meanwhile lost its 

 lamellated appearance and becomes homogeneous looking, 

 is gelatinized from the hilum outwards without any dis- 

 eemible fissuring until only a nearly transparent mass 

 remains at the distal margin, and this may present a 



