GENtrS BRODTiEA. 591 



Reactiou with chromic acid begins in some of the smaller grains in 30 seconds and is general 

 in 3 to 4 minutes; all the grains are dissolved in 10 minutes. This reaction is slow and even; it does 

 not start rapidly and then become slower, as is common with most starches. The hilum is very 

 prominent. The lamellae are fairly distinct, the hilum swells, the fissures widen, and the grain 

 becomes covered with fine, radiating striae. The inner portion is reduced to a granular, gelatinous 

 mass. The peripherally located starch forms a ring which at first is thick and distinctly striated, 

 with a ragged, inner border, which subsequently gradually becomes thinner and transparent as the 

 grain swells, until a large, smooth, thin-walled, gelatinized grain is formed. This cajjsule dissolves 

 at one end, and the inner mass flows out and disappears. The rest of the capsule dissolves rapidly. 



The reaction wth pyrogaUic acid begins in some of the grains in 30 seconds and is general in 2 

 minutes. The grains are entirely gelatinized in 10 minutes. Both hilum and the lamellse become 

 very distinct. The hilum swells and the fissures ^viden and deepen. The grain is divided by fine, 

 radiating fissures. The inner part of the grain is changed into a gelatinous mass. The marginal 

 part forms a ring which at first is thick and opaque and shows fine strise, and also concentric, alter- 

 nate refractive and non-refractive bands. As the grain continues to swell, this ring becomes thinner 

 and clearer and divided by internal fissures until a thin, transparent, gelatinous capsule forms. 

 The swollen grains are large, and if the original gi'ains are fissured they are somewhat lobulated and 

 distorted; but if not fissured, they are smooth and retain much of the original shape of the grains. 



Reaction with ferric chloride begins in a few grains in a minute and the reaction is over in them 

 in 7 minutes. Other grains at this time are as yet unaffected, but in 9 to 10 minutes many begin 

 to react. In 15 minutes about one-third are swollen; in IJ^ hours about two-thirds are gelatinized; 

 and in 13^ hours all are gelatinized. The hilum becomes prominent, but the lamella; are obscured. 

 The reaction begins at projecting points on the chstal end and sides, and proceeds over the grain 

 until only a small portion about the hilum remains ungelatinized. This latter becomes split by 

 many fissures, the pieces rapidly breaking apart and gelatinizing separately. The swollen grains 

 are large, irregular, sacculated, and wrinkled. In some grains the hilum merely swells, and then 

 the inner portion, followed by the marginal portion, is altered into a gelatinous mass. These gela- 

 tinized grains are not so large or so irregular or sacculated as those first described. 



With Purdy^s solution there is slight reaction in a few grains in 1}/^ minutes, but only a few are 

 completely gelatinized and a few others show the beginning of gelatinization after an hour. Both hilum 

 and lamella; become very prominent. The hilum enlarges, and the grain is divided by fine, radial fis- 

 sures. The inner part is transformed into a gelatinous mass, much of which appears to be forced to 

 the base of the grain. The marginal part of the gi-ain is differentiated into a thick, striated ring, 

 which shows three or four concentric refractive and non-refractive bands. The ring later becomes a 

 thin, transparent capsule. The gelatinized grains are large and somewhat wrinkled, but not lobulated. 



STARCH OF BRODI^A IXOIDES VAR. SPLENDENS. (Plate 45, figs. 267 and 268. Chart 172.) 



Histological Characteristics. In form the grains are simple with the exception of a few com- 

 pounds; nearly all are isolated; there are few clumps, and no pressure facets. The surface may be 

 irregular, owing not only to irregular development of the margin, but also to amorphous additions 

 to the surface. The conspicuous forms are the elongated ovoid, broad ovoid, and long and short 

 ellipsoidal. There are also round or nearly round, pyriform, irregularly triangular, and polygonal 

 grains, and various irregular forms. The compound grains have very irregular shapes, and commonly 

 are irregularly ellipsoidal. The grains are not flattened and are of the same or nearly the same 

 thickness and width at any given transverse diameter. The distal end is usually narrower than 

 the proximal. 



The hilum is usually distinct when not fissured. It appears as a small round spot, and eccentric 

 about one-third of the longitudinal axis of the grain, and commonly in the larger end of the grain. 

 There may be two or more hila placed irregularly with respect to one another. The hilum is often 

 fissured by a large or small, ragged or clear-cut, single, transverse or diagonal cleft; or a 3-armed, 

 or a large irregular cruciate fissiue. 



The lainelloB are not very distinct. They appear to be rather coarse, regular, continuous rings, 

 which follow the outline of the margin of the grain, but not of the amorphous additions; more dis- 

 tinct near the hilum. The average number on a grain could not be determined with any accuracy. 



The grains var}' in size from 3 to 38yu. The common size is 26;u. The common dimensions 

 of large grains are 34 by 2G/i in length and breadth. 



