398 



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



or nearly centric hilum is the most resistant. The grains 

 now assume a pitted appearance followed by the breaking 

 of the starch into irregular refractive masses and gran- 

 ules previous to gelatinization. In all methods refrac- 

 tive granules may precede complete gelatinization, and 

 in the grains where the reaction begins at one or two 

 ends, well-defined fissures often proceed either from the 

 hilum or intersect this region, and become quite deep 

 and branched at the one or two extremities. As the 

 reaction approaches the proximal end and sides nearby, 

 it is quite characteristic for one side to gelatinize more 

 quickly than the other. The narrow resistant band of 

 starch is often penetrated by deep, short fissures previous 

 to breaking into linear granules. The capsule is delicate 

 and is much distorted and considerably distended during 

 the process. The gelatinized grains are swollen and 

 slightly to considerably distorted so that they do not bear 

 much resemblance to the form of the untreated grain. 



The reaction with chromic acid 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 

 4 per cent of the total starch in 5 minutes; in about 67 

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

 in 15 minutes; in about 80 per cent of the grains and 

 98 per cent of the total starch in 20 minutes ; in 100 per 

 cent of the grains and total starch in 25 minutes. (Chart 

 D23.) 



The reaction with pyrogallic acid begins in 1 minute. 

 Complete gelatinization occurs in about 5 per cent of the 

 grains and 6 per cent of the total starch in 5 minutes ; in 

 about 30 per cent of the grains and 65 per cent of the 

 total starch in 15 minutes; in about 57 per cent of the 

 grains and 86 per cent of the total starch in 30 minutes ; 

 in about 75 per cent of the grains and 90 per cent of the 

 total starch in 45 minutes; in about 90 per cent of the 

 grains and 97 per cent of the total starch in 60 minutes. 

 (Chart D24.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 1 per cent of the 

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

 in 5 minutes; in about 7 per cent of the grains and 

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

 11 per cent of the grains and 40 per cent of the total 

 starch in 30 minutes; in about 18 per cent of the grains 

 and 48 per cent of the total starch in 45 minutes; in 

 about 20 per cent of the grains and 53 per cent of the 

 total starch in 60 minutes. (Chart D 25.) 



The hilum swells but no bubble is seen there. The 

 entire grain becomes very refractive and the lamellae do 

 not usually become any more distinct, with the exception 

 of one clear lamella which is sometimes observed forming 

 a line of demarcation between the main body of the grain 

 and a border which is little if any more refractive than 

 the rest of the grain. One or two fissures, according to 

 the shape of the grain, either proceed from the hilum 

 when it is quite eccentric, or one fissure may intersect the 

 hilum if this point is centric or slightly eccentric. These 

 fissures are usually deep and often much branched. Gela- 

 tinization of the grain is much varied and is often fol- 

 lowed by partial and sometimes complete solution. In 

 grains with an eccentric hilum gelatinization starts at the 

 distal margin and advances towards the proximal end; a 

 band at the proximal end and sides nearby being the 

 most resistant, one side of the proximal end gelatinizing 



before the other. In many grains, notably those of a 

 rounded or ellipsoidal type, the reaction spreads quite 

 rapidly through the mesial region with the appearance of 

 irregularly massed very refractive granules, a very refrac- 

 tive border becomes profusely striated and the outer 

 lamellae are broken down into linearly arranged refractive 

 granules; the granules of one outermost lamella may 

 prove very resistant and in some grains the capsule after 

 much distention may be ruptured and deeply slashed 

 at several points. The reaction may start in the mar- 

 ginal border and extend around the entire grain, some- 

 times with some ruffling, but more frequently the outer- 

 most lamella is broken into linearly arranged refractive 

 granules which are very resistant. In elongated grains 

 with a centric or slightly eccentric hilum the process 

 may start almost simultaneously at both ends and then 

 advance towards the hilum, a narrow band for a short 

 distance at either side of the hilum proving the most re- 

 sistant. All the methods of gelatinization are preceded 

 by the disorganization of the starch into very refractive 

 granules. 



The gelatinized grains are swollen and slightly to 

 considerably distorted. Many grains are but partially 

 gelatinized, a refractive band and very refractive gran- 

 ules often proving resistant, and some of the grains are 

 but slightly affected by the reagent beyond the fissuration 

 already noted at the beginning of the reaction. 



The reaction wit/i sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 28 per cent of the 

 entire number of grains and 60 per cent of the total starch 

 in 5 minutes ; in about 72 per cent of the grains and 90 

 per cent of the total starch in 15 minutes; in about 94 

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

 in 30 minutes. (Chart D 26.) 



The reaction with hydrochloric acid begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 1 per cent of the entire number of grains and 2 

 per cent of the total starch in 5 minutes; in about 12 

 per cent of the grains and 25 per cent of the total starch 

 in 15 minutes; in about 15 per cent of the grains and 

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

 per cent of the grains and 43 per cent of the total starch 

 in 45 minutes ; in about 29 per cent of the grains and 58 

 per cent of the total starch in 60 minutes. (Chart D 27.) 



The reaction with potassium hydroxide begins in a 

 few grains immediately. Complete gelatinization occurs 

 in about 4 per cent of the entire number of grains and 

 6 per cent of the total starch in 5 minutes ; in about 14 

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

 in 15 minutes ; in about 16 per cent of the grains and 48 

 per cent of the total starch in 30 minutes ; in about 28 per 

 cent of the grains and 54 per cent of the total starch in 

 45 minutes ; in about 32 per cent of the grains and 56 per 

 cent of the total starch in 60 minutes. (Chart D 28.) 



The reaction with potassium iodide begins in a very 

 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 ; very slight progress in 15 

 minutes ; and in about 1 per cent of the grains and 2 per 

 cent of the total starch in 30 minutes ; in about 2 per cent 

 of the grains and 4 per cent of the total starch in 45 

 minutes ; in about 3 per cent of the grains and 8 per cent 

 of the total starch in 60 minutes. (Chart D 29.) 



