538 



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



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

 24 per cent of the grains and 35 per cent of the total 

 starch in 60 minutes. (Chart D 287.) 



The hilum is at first indistinct, until a small bubble 

 is formed there in most of the grains. The lamellae 

 also are indistinct at first in all the grains, but later 

 become moderately distinct in a small majority and 

 remain indistinct in the rest. The grains all become 

 somewhat more refractive, the first portion of the grain 

 to be so affected is a rather narrow band of starch 

 at the margin. Gelatinization begins at discrete points, 

 usually protuberances from the distal margin or sides 

 nearby, and sometimes from the proximal end or sides 

 nearby, and proceeds from these points as if converging 

 toward a common center, hollowing out deep, cup-shaped 

 cavities in the grain as it advances. The substance of 

 the grain becomes brilliantly refractive just in advance 

 of gelatinization and is invaded by rather indistinct 

 fissures which separate particles of varying size. As 

 the process of gelatinization nears the hilum, the bubble 

 usually shrinks and disappears, or swells first, and then 

 shrinks and disappears; and in the majority of the grains 

 a refractive fissure is seen to form and extend from the 

 hilum through the center of the ungelatinized material 

 to the gelatinized portion, splitting the ungelatinized 

 portion into two parts which are separated rather widely 

 and gelatinize independently of one another, one usually 

 becoming gelatinous before the other. In some grains the 

 fissure from the hilum does not form and gelatinization 

 continues from the distal margin until the proximal end 

 is reached, the starch at the proximal end being the 

 most resistant in all the grains. 



The gelatinized grains are somewhat swollen and 

 have thin capsules, they are much distorted, and do not 

 retain any resemblance to the form of the untreated 

 grain. 



Comparison of the Moral hydrate reactions between 

 N. poeticus ornatus and N. gloria mundi shows : 



A bubble is formed in somewhat fewer grains and 

 the lamellae are more distinct than in N. gloria mundi. 

 The grains become more refractive in appearance and 

 the band of material at the margin, which is the first 

 part so affected, is broader than in N, gloria mundi. 

 Gelatinization progresses according to two methods. The 

 majority of the grains are gelatinized rather differently 

 from those of N. gloria mundi, the main points of differ- 

 ence being that gelatinization extends first around the 

 whole margin which is first partially separated from the 

 rest by a fissure, except a small portion at the proximal 

 end; it then proceeds inward with more fissuring and 

 separation of particles from the ungelatinized material. 

 The second method which occurs in the lenticular-shaped 

 grains is not seen in N. gloria mundi. The gelatinized 

 grains are more swollen, have thinner capsules, and 

 are more distorted than in N. gloria mundi. 



The reaction with chromic acid begins in 1 minute. 

 Complete gelatinization occurs in less than 0.5 per cent 

 of the entire number of grains and 2 per cent of the total 

 starch in 5 minutes ; in less than 1 per cent of the grains 

 and 25 per cent of the total starch in 15 minutes; in 

 about 4 per cent of the grains and 65 per cent of the 

 total starch in 30 minutes; in about 21 per cent of the 

 grains and 82 per cent of the total starch in 45 minutes ; 

 in about 26 per cent of the grains and 90 per cent of 



the total starch in 60 minutes. (Chart D 288.) (See 

 footnote, page 516.) 



The hilum is distinct and the lamellae are not very 

 distinct at first, but become more distinct as the reac- 

 tion progresses. Gelatinization begins at the hilum and 

 progresses according to but one method in all but rare 

 grains. Two furrows or, in many grains, actual fissures 

 proceed from the hilum transversely or slightly obliquely 

 to the margin, and just distal to these fissures and parallel 

 with them a number of irregular fissures (looking like 

 a sheaf of wheat or straw) radiate from the hilum. The 

 rest of the starch included between the original fur- 

 rows or fissures and the margin becomes finely granu- 

 lar, except a rather narrow portion at the margin, which 

 is striated and has a spicular inner border. The less 

 resistant material begins to gelatinize and the grains 

 to swell. The fissures become wider and the part of the 

 grain which they traverse is divided into rather coarse 

 granules that are quickly gelatinized. The material 

 at the proximal end and sides nearby, which is the most 

 resistant part of the grain, is striated and, as the grain 

 swells, is pushed to the margin where it, with the narrow 

 band of material around the rest of the margin, forms a 

 marginal band that is gelatinized more rapidly at the 

 distal end and remains at the proximal end for a long 

 time after the rest of the grain is gelatinized. 



The gelatinized grains are much swollen, have rather 

 thin capsules, and are somewhat but not greatly dis- 

 torted. The capsule in a number of the grains is dis- 

 solved at one point before gelatinization is complete, 

 the contents flow out gradually and are dissolved, leaving 

 only a portion of the capsule which is slowly dissolved. 



Comparison of the chromic acid reactions between 

 N. poeticus ornatus and N. gloria mundi shows : 



The hilum and lamella are both more distinct. 

 Gelatinization progresses according to two types, 

 neither of which is seen in N. gloria mundi. In the 

 majority of the grains the material immediately sur- 

 rounding the hilum is divided by fissures into large 

 granules, and longitudinal fissures extend to the distal 

 margin from the hilum. The rest of the material of 

 the grain is divided by coarse strias. The less resistant 

 starch is gelatinized especially between the hilum and 

 the distal end, the more resistant material forms a mar- 

 ginal band consisting of two layers, an outer striated 

 and lamellated, and an inner spicular one. The in- 

 terior of the grain meanwhile is filled with rather coarser 

 granules which gelatinize more rapidly than the marginal 

 band. The marginal band is gelatinized more rapidly 

 at the distal end than elsewhere, and finally only the 

 capsule is left. The second method is very much like 

 the first, except that the granules are formed from the 

 primary starch and are very resistant, and there is only 

 one part to the band at the margin, and this is striated 

 and lamellated. The gelatinized grains are not so much 

 swollen, have thicker capsules, and are less distorted than 

 in N. gloria mundi. Fewer grains are dissolved before 

 gelatinization is complete than in N. gloria mundi. 



The reaction with pyrogallic acid begins 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 2 per cent of the grains 

 and 18 per cent of the total starch in 15 minutes; in 

 about 17 per cent of the grains and 65 per cent of the 



