568 



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



depressions in the grain, which become gradually wider 

 and deeper until they coalesce. The hilum is reached 

 by this time, it swells moderately rapidly, and the ma- 

 terial immediately surrounding it is rapidly gelatinized. 

 The gelatinized grains are not greatly swollen, and have 

 rather thick capsules. They are much distorted, but 

 retain some resemblance to the form of the xintreated 

 grain. 



Comparison of the chloral-hydrate reactions between 

 N. albicans and N. empress shows: 



A bubble is much more frequently found at the 

 hilum and is smaller than that formed in the grains of 

 N. empress. The lamella, which are not distinct at 

 first, later become more distinct than in N, empress, and 

 the grains grow somewhat more refractive after the 

 reagent is added. Gelatinization as in N. empress be- 

 gins in the majority of the grains at various points on 

 the margin, and progresses according to the two methods 

 described in that starch. The progress of gelatinization 

 is smoother, and serial separation of the lamella? and 

 cracking and fissuring of the ungelatinized material does 

 not occur. The gelatinized grains are somewhat swollen 

 and have thinner capsules and are somewhat more dis- 

 torted than in N. empress. 



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 0.5 per cent of 

 the grains and 45 per cent of the total starch in 15 

 minutes; in about 20 per cent of the grains and 92 per 

 cent of the total starch in 30 minutes; in about 65 per 

 cent of the grains and 98 per cent of the total starch in 

 45 minutes ; and in about 90 per cent of the grains 

 and in more than 99 per cent of the total starch in 60 

 minutes. (Chart D 318.) (See footnote, page 516.) 



The hilum becomes distinct, unattended by the for- 

 mation of a bubble. The lamellae also become distinct, 

 but usually are obscured during the reaction. Gela- 

 tinization begins at the hilum and progresses according 

 to three methods. In the first method, which is seen in 

 a smnll majority of the grains, the primary starch imme- 

 diately around the hilum is divided by fissures into two 

 to four portions, which are again divided into many fine 

 granules by irregular fissuring. The secondary starch 

 is divided by fine stria? and loses its lamellated appear- 

 ance. The granular primary starch begins to gelatinize 

 and the grains to swell. The less resistant portion of 

 the secondary starch is also gelatinized and the more 

 resistant part forms a finely striated band at the mar- 

 gin, which has a spicular inner border. The interior 

 of the grain is granular first and then becomes clear 

 and the marginal band gradually becomes thinner and 

 more nearly transparent, until it also is gelatinized and 

 only the capsule is left. In the second method, which is 

 seen in a moderate number of grains, a sheaf of irregular 

 fissures extends from the hilum to the distal margin, 

 dividing the starch in their path into rather coarse, 

 irregular granules which begin to gelatinize. The rest 

 of the grain is finely striated, and as the granular mate- 

 rial is gelatinized and the grain swells, this striated 

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

 marginal band which does not extend completely around 

 the margin. At the point where it is not complete the 

 capsule is dissolved and the contents of the grain flow out 



and are dissolved. In the third method, which is also 

 seen in a moderate number of grains, 2 furrows or actual 

 fissures extend horizontally or obliquely from the hilum 

 to the margin and the material just distal to the hilum 

 is divided by fissures into coarse granules and the rest 

 of the starch distal to the hilum and the furrows loses 

 its lamellar structure and becomes a finely granular mass 

 which is afterwards divided by irregular longitudinal 

 fissures radiating from the hilum. The proximal mate- 

 rial is finely striated and is very resistant. The grain 

 swells slowly and in most of the grains the granular distal 

 portion is gelatinized and the capsules dissolved before 

 the proximal starch shows any sign of change ; in others 

 it becomes more refractive in appearance and somewhat 

 thinner, but is never completely gelatinized before solu- 

 tion occurs. The gelatinized grains are much swollen, 

 have rather thin capsules, and are considerably distorted. 



Comparison on the chromic-acid reactions between 

 N. aTbicans and N. empress shows : 



The hilum and lamella? are as distinct as in N. em- 

 press. Gelatinization progresses according to two in- 

 stead of three methods. The first method, which is seen 

 in a small majority of the grains, resembles closely the 

 second method described for a moderate number of 

 grains of N. empress, the only difference noted being 

 that 2 sheaves of fissures sometimes extend from the 

 hilum to the margin, one to the distal and one to the 

 proximal end, and the capsule is dissolved at these 

 two points instead of at but one. The second method, 

 which is seen in a large minority of the grains, is nearly 

 the same as the third method, which is seen in a moderate 

 number of grains of N. empress; the difference noted is 

 that the material distal to the hilum and the horizontal 

 furrows from the hilum is divided by coarse stria? into 

 rows of .granules arranged according to the rows of 

 lamellrp, instead of losing its structural appearance and 

 becoming a finely granular mass. The grains are always 

 dissolved before they are completely gelatinized. 



The reaction with pyrogallic acid begins in 1 minute. 

 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 4 per cent of the grains 

 and 13 per cent of the total starch in 15 minutes ; in about 

 27 per cent of the grains and 50 per cent of the total 

 starch in 30 minutes ; in about 39 per cent of the grains 

 and 61 per cent of the total starch in 45 minutes ; and in 

 about 44 per cent of the grains and 78 per cent of the total 

 starch in 60 minutes. (Charts D 319 and D 320.) 



The hilum is distinct and a bubble is never formed 

 there. The lamellae are distinct, and often some traces 

 of a lamellar structure remain at the margin after the 

 rest of the grain is completely gelatinized. Gelatiniza- 

 tion begins at the hilum and follows two methods of 

 procedure. In the first, which is seen in a majority of 

 the grains, the portion immediately surrounding the 

 hilum is split into many fine particles or granules, which, 

 as the grain swells, are widely scattered. The rest of the 

 grain is divided by fine striae and 2 refractive fissures 

 that extend obliquely from some point near the hilum to 

 the margin ; the portion of the grain included between 

 these 2 fissures becomes more refractive and homogene- 

 ous-looking, and gelatinizes before the rest of the grain. 

 The rest of the starch is divided into rows of fine 

 granules which are arranged in rows corresponding to the 



