802 STARCHES OF CANNACEiE. 



Effects of Various Reagents. — ^With chloral hydrate-iodine reaction begins in IJ^ minutes. Most 

 grains are entirely gelatinized in 10 minutes and all in 18 minutes. The hilum and lamellse disap- 

 pear. The margin becomes clearer and darker, which by contrast causes the inner portion of the 

 grain to appear lighter and opaque. The one or two shoulder-like projections near the proximal 

 end, or projections elsewhere, become dark and swollen, and the changes are followed by the dark- 

 ening and swelling of other parts. The hilum and one or two nearby marginal points protrude as 

 very long projections, the hilum swelUng first and the reaction extending to the margin. The result 

 of this is the formation of a ring of indigo-colored, gelatinized starch surrounding a violet-tinted, 

 ungelatinized central mass which later is gradually included in the process. The gelatinized grains 

 are large, irregularly rounded, and show a number of irregular bands of dark material separated by 

 fissural hues in the distal portion. The marginal portion often breaks away in long strips from the 

 rest of the grain, while in the central part a dark mass remains which is often fissured in one or two 

 directions. At the proximal end there are often narrow projections. 



Reaction with chromic add begins in 15 seconds and is over in 2J^ minutes. The hilum and 

 lamellse are distinct. A line extends out transversely on each side of the hilum. The hilum swells 

 greatly, and the inner portion of the grain becomes divided by fine cross-fissures into a number of 

 granules. The margin at the hilum is dissolved and the capsule opens out. One or rarely two large 

 crescents containing several lamellse now appear at the distal end of the grain and may separate 

 and dissolve separately. Often they do not separate, but gradually become clear and finally dis- 

 appear with the rest of the grain, the inner granular portion disappearing last. 



The reaction with pyrogallic add begins in 30 seconds and ends in 20 minutes. The hilum and 

 lamellse are distinct. A refractive line extends from each side of the hilum, the hilum swells, and 

 three or four deep fissures radiate through the substance of the grain, open out as the hilum con- 

 tinues swelling, and the grain is thus divided into small pyramids which become divided and re- 

 peatedly subdivided as the grain swells, and finally pass into a granular gelatinous mass. The 

 gelatinized grains are large and rounded or reniform in shape. At the proximal end there is a clear 

 space representing the swollen hilum, and at the distal end a series of concentric folds, which may be 

 lobulated and much distorted. 



Reaction with ferric chloride begins in 4 minutes and is over in 45 minutes. The hilum and 

 lamellse disappear. The margin of the grain becomes clear and dark and a few lamellse reappear 

 within it. The clearing and darkening spread inward and involve the central portion of the grain. 

 Swelling with great protrusion begins at either one or both of the projections of the proximal end. 

 A small crack or fissure appears in the margin at the point at which protrusion occurs, distending a 

 gelatinized capsule. From this point the grain may proceed to swell in one of two ways: Either a 

 ring of gelatinization extends from the two points already mentioned around the margin, which is 

 followed by swelling and great protrusion of the hilum, leaving a central unswollen portion which 

 becomes divided by fissures into several pieces which subsequently gelatinize; or the hilum may swell 

 first and gelatinization proceed distally with fissuring throughout the grain, the distal end being 

 affected last. Occasionally the grain may begin to swell at both ends and at indifferent points on 

 the margin. The gelatinized grains are large and very much folded, crumpled, and distorted. The 

 proximal end is characterized by two or three long, finger-like projections, and the distal end by 

 a crumpled, irregular mass. 



The reaction with Purdy's solution begins in 15 seconds. Most grains are gelatinized in IJ^ 

 minutes and all in 3 minutes. The hilum and lamellse become very distinct and a refractive line 

 extends on each side from the hilum, and the hilum swells slowly and then very rapidly. As the 

 swelling extends distally over the whole grain, the grain dissolves rapidly or slowly, as the case may 

 be Usually there is no fissuration or only very fine fissures appear, or occasionally there may be 

 deep fissures which radiate from the swollen hilum and open out as the grain swells, thus dividing 

 the substance of the grain into four or five pyramidal parts. No longitudinal fissuring of the grain 

 occurs. The gelatinized grains are large, somewhat ovoid, or round; they show a clear space with 

 little projection outward at the proximal end, representing the swollen hilum and a rounded portion 

 below, with either concentric rows or folds and sacculations. 



STARCH OF CANNA VAR. (KONIGEN CHARLOTTE). (Plate 84, figs. 499 and 500. Chart 339.) 



Histological Characteristics. — Inform the grains are simple with the exception of rare compoimds. 

 There are no aggregates, clumps, or pressure facets. The surface is usually quite regular except 

 for rounded or nipple-like protuberances at the side or at either end of the grain. The primary 



