GENUS CROCUS. 746 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins immediately. A few 

 grains are gelatinized in 30 seconds, about half in a minute, about nine-tenths in 2 minutes, and all 

 but rare resistant grains in 3 minutes. The reaction is complete in the latter in 53^ minutes. The 

 grains color a light red-violet immediately, and either a dark ring or irregular looped structure is 

 occasionally formed at the hilum. Gelatinization begins at the pressure facets and a dark rim of 

 color appears here, which spreads first around the margin of the grain or along ridges on the surface 

 when such are present. Occasionally small protuberances are formed at the corners of the grains 

 during gelatinization. Gelatinization begins uniformly around the surface of round grains and 

 spreads towards the center. In the more resistant grains an old-rose tint precedes the deep-blue 

 coloring, which indicates the occurrence of gelatinization. The gelatinized grains are much swollen, 

 but retain the shape of the untreated grain. 



The reaction begins at once with chromic acid. A few grains are dissolved in 20 seconds, a 

 majority in 30 seconds, all but rare resistant grains in 45 seconds, and all in 75 seconds. Lamellse 

 not seen in the normal grain become distinct, the hilum swells, and two or more radiating fissures 

 proceed from it. The interior of the capsule is quickly dissolved, the grain swells, and finally the 

 capsule is ruptured at one or more points and the entire grain is dissolved. 



Reaction begins with pyrogallic acid immediately. A few grains are gelatinized in 10 seconds 

 and all in 30 seconds. The hilum swells, fissures radiate from it to the corners of the grain, and 

 gelatinization proceeds so rapidly that the details can not be satisfactorily determined. Occasionally 

 a bubble forms at the hilum, which appears temporarily to retard the reaction; it then enlarges 

 and finally collapses, followed by rapid gelatinization of the grain. In the round grains the hilum 

 swells and numerous fine radiating fissures proceed from it. 



The reaction with ferric chloride begins in a few grains in 30 seconds; several are gelatinized 

 in a minute, practically all are in various stages in 3 minutes, the majority are gelatinized in 

 5 minutes, and all but a few resistant grains in 10 minutes. The reaction is complete usually in 

 18 minutes, rarely 25 minutes. The hilum, or cleft located at this point, swells, and a bubble 

 often collects there. Gelatinization now begins at the facets, the process spreads quickly around 

 the margin of the grain, the starch in the center being the most resistant. This less soluble 

 starch is broken forcibly into fragments, which are finally gelatinized. The most resistant grains 

 are the forms with regular outline, in which either the cavity or cleft at the hilum gradually 

 enlarges until finally collapse occurs and a succession of bubbles is expelled, followed by the 

 rapid gelatinization of the grain. The grains are swollen, but retain the general shape of the 

 untreated grain. 



Reaction begins immediately with Purdy's solution. A few rather small grains are gelatinized 

 in a minute, and all are in various stages of dissolution in 5 minutes. About one-third are gelatinized 

 in 10 minutes, more than half in 15 minutes, and all in 30 minutes, except a few of the round or the 

 dome-shaped type. The hilum swells and fissures radiate from it to the corners of the grain. A 

 bubble is rarely formed at the hilum. The starch fining the capsule becomes delicately striated and 

 rarely evidence of lamellse may be observed. Gelatinization usually proceeds around the hilum and 

 along the fissures, accompanied by uniform swelling of the grain. Occasionally the starch at the 

 proximal end is gelatinized rather rapidly, accompanied by a distension of the capsule, and a center 

 of gelatinization then begins at the facets located at the distal end, with similar swelling. Gelatini- 

 zation advances from these two centers towards each other, from the proximal with the greater 

 rapidity, until the whole grain is involved. In the round grains the hilum swells, the previously 

 unseen lamellae become fairly distinct and striated, and gelatinization proceeds slowly until the 

 reaction is complete. A narrow border of resistant starch is not completely gelatinized. The gelat- 

 inized grains are swollen, but retain the shape of the untreated grains. 



STARCH OF CROCUS VERSICOLOR (CLOTH-OF-SILVER). (Plate 74, figs. 443 and 444. Chart 290.) 

 Histological Characteristics. — In form the grains are simple, partly isolated, and partly either 

 in aggregates which consist of two or more components or in clumps consisting of many grains. 

 Well-marked pressure facets are found on most of the isolated grains. The irregularities of some 

 grains are due to the same causes as those noted for C. susianus (Cloth-of-Gold). The conspicuous 

 forms are the polygonal, dome-shaped with either a flattened or pointed distal end, and roimd or 

 nearly round. Compared with C. susianiis (Cloth-of-Gold) the proportion of dome-shaped, round 

 and nearly round, and ellipsoidal grains is much greater; the grains are more regular in outline 



