594 



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



at the margin grows slowly thinner and more nearly 

 transparent and is finally gelatinized, that at the proxi- 

 mal being the last. A few of the grains are dissolved 

 before gelatinization is complete. The gelatinized grains 

 are much swollen, have rather thin capsules, and are not 

 much distorted. 



Comparison of the chromic-acid reactions between 

 N. triandrus albus and N. emperor shows : 



The hilum and lamellae are not quite so distinct as 

 in N. emperor. Gelatinization progresses according to 

 two methods instead of but one as in N. emperor. In 

 the first, which is seen in a majority of the grains and 

 which is in some respects similar to that seen in N. 

 emperor, the primary starch around the hilum is broken 

 up into very fine granules and a sheaf of irregular fissures 

 extends to the proximal and to the distal margins. From 

 this point the reaction is the same as in N. emperor, 

 except that the marginal band is more rapidly gelatinized 

 at the proximal and the distal ends than at the sides, 

 while the primary starch is gelatinized before the sec- 

 ondary instead of afterwards, as is often the case in N. 

 emperor. In the second method, which is also similar in 

 some respects to that seen in N. emperor, 2 furrows or 

 fissures extend transversely or obliquely from the hilum 

 on either side to the margin, and from this point the 

 reaction is the same as in N. emperor, except that there 

 is no distinction between primary and secondary starch, 

 and the band of resistant material at the margin is 

 formed only at the proximal end and not all around the 

 margin as in N. emperor. The grains are all gelatinized 

 before they are dissolved. The gelatinized grains are 

 more swollen, have thinner capsules, and are somewhat 

 more distorted than in N. emperor. 



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 5 per cent of the 

 total starch in 5 minutes; in about 2 per cent of the 

 grains and 20 per cent of the total starch in 15 minutes; 

 in about 47 per cent of the grains and 74 per cent of the 

 total starch in 30 minutes; in about 60 per cent of the 

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

 and in about 70 per cent of the grains and 93 per cent of 

 the total starch in 60 minutes. (Charts D 343 and 

 D344.) 



The hilum becomes distinct, unattended by the for- 

 mation of a bubble. The lamellae are distinct and evi- 

 dence of a lamellar structure persists throughout the 

 greater part of the reaction. Gelatinization begins at 

 the hilum, and in nearly all the grains proceeds according 

 to but one method. The primary starch immediately 

 surrounding the hilum is split into four or five portions, 

 which are in turn subdivided into a number of rather fine, 

 refractive granules which are widely scattered as the 

 grain swells. The secondary deposit surrounding the 

 primary starch is divided by fine striae, and as the less 

 resistant starch is gelatinized the more resistant portion 

 is pushed to the margin, where it forms a finely striated 

 and distinctly lamellated band, around the inner bor- 

 der of which are scattered the granules of the primary 

 starch which remain ungelatinized until the secondary 

 starch is gelatinized. The marginal band is gelatinized 

 more rapidly at the distal end and last at the proximal 

 end. In a few grains, 2 furrows or fissures extend from 

 the hilum on either side of the margin. The material 



distal to them becomes finely granular and gelatinizes 

 slowly; the proximal material forms a homogeneous- 

 looking band at the proximal margin and remains un- 

 gelatinized. The gelatinized grains are considerably 

 swollen, have rather thick capsules, and are somewhat 

 distorted. 



Comparison of the pyrogallic-acid reactions between 

 N. triandrus albus and A", emperor shows : 



The hilum and lamellae are not quite so distinct as in 

 N. emperor. Gelatinization progresses according to 

 three methods instead of but two as in N. emperor. 

 The first, which is seen in a large number of grains, 

 corresponds with that which is described for a very few 

 grains of N. emperor, the only difference being that the 

 material proximal to the 2 furrows or fissures which ex- 

 tend transversely or obliquely from either side of the 

 hilum to the margin forms a homogeneous-looking band 

 at the proximal margin instead of being covered by fine 

 striae. The second method, which is seen in a large num- 

 ber of the remaining grains, is not noted in N. emperor. 

 The hilum enlarges somewhat, and the grain is covered by 

 fine stria?, and gelatinizes and swells slowly; the more 

 resistant material forms a finely striated band at the mar- 

 gin which very slowly becomes thinner and more nearly 

 transparent until it is completely gelatinized. The third 

 method, which is seen in an equal number of grains as 

 the second, corresponds with that described for the great 

 majority of the grains of N. emperor; the only differ- 

 ences noted are that the granules into which the primary 

 starch is divided are larger and more refractive, and 

 the strias in the secondary starch are not so fine and 

 more distinct. The gelatinized grains are more swollen, 

 the capsules are not so thick, and they are more distorted 

 than in N. emperor. 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 1 per cent of the 

 entire number of grains and 10 per cent of the total 

 starch in 5 minutes ; in about 16 per cent of the grains 

 and 51 per cent of the total starch in 15 minutes; in 

 about 31 per cent of the grains and 62 per cent of the 

 total starch in 30 minutes; in about 35 per cent of the 

 grains and 65 per cent of the total starch in 45 minutes; 

 and in about 37 per cent of the grains and 67 per cent 

 of the total starch in 60 minutes. (Chart D 345.) 



The hilum is distinct and occasionally a bubble is 

 formed there immediately after the reagent is added, but 

 it soon shrinks and disappears. The lamellae are distinct, 

 and evidence of a lamellar structure remains throughout 

 the greater part of the reaction. Gelatinization begins 

 at the hilum and in nearly all the grains progresses by 

 one method. The material immediately surrounding the 

 hilum, which probably represents a primary starch for- 

 mation, is split into several particles which are usually 

 subdivided and scattered as the grain swells, but which 

 sometimes remain clumped together in their original 

 position while the rest of the grain is gelatinized. In 

 the meantime, the material surrounding the primary 

 starch, which probably represents a secondary starch 

 formation, is first divided by fine striae, and as the less 

 resistant portion is gelatinized the more-resistant ma- 

 terial is pushed to the margin, where it forms a finely 

 striated and distinctly lamellated band, around the inner 

 border of which are usually arranged the particles of the 

 primary starch. The marginal band at the distal end is 



