GENUS CHIONODOXA. 547 



completely gelatinized, the solution is colored very lightly and the swollen grains very deeply on 

 the addition of iodine. After boiling for 2 minutes the solution colors very deeply, but the grain- 

 residues much less deeply. All the capsules contain some blue-reacting starch, and with an excess 

 of iodine they become a light violet. 



Staining Reactions. — With gentian violet and with safranin the grains begin to stain very lightly 

 in 30 seconds, and after 30 minutes are fairly stained, one grain as deeply as another. 



Temperature Reaction. — The temperature of gelatinization is 59.4° to 60.6° C, mean 60°. 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins in a minute and almost 

 all grains are gelatinized in 15 minutes. Both hilum and lamellae are rendered distinct. The more 

 prominent points on the reacting grain are the projections on the margin, which darken and some- 

 times swell to a marked degree around the whole margin, the swelling is very even, and the unswollen 

 central part of the grain is thus surrounded by a dark band. The inner part of the grain then darkens 

 gradually and when the hilum is reached the grain as a whole swells. The swollen grains are very 

 large and show a very dark center surrounded by three or four concentric dark rings, sometimes 

 broken irregularly, and separated from one another quite evenly by lighter spaces. 



Reaction with chromic add begins immediately and is over in 2 minutes. The hilum swells 

 rapidly and the inner portion is transformed rapidly into a gelatinous mass, leaving a very thin 

 marginal ring, which at first shows fine striae and several alternately refractive and non-refractive 

 concentric bands. This ring is soon altered into a very thin, homogeneous, transparent envelope 

 which at the thinnest point, either at the proximal or distal end, invaginates and dissolves, the 

 contents passing out and disappearing, followed by solution of the rest of the envelope. The grains 

 swell to an enormous size before dissolving. 



Reaction with pyrogallic acid begins in 10 seconds and is complete in nearly all the grains in 

 2 minutes. A very few are only partially gelatinized. Both hilum and lamellae are rendered very 

 distinct. The hilum begins to swell evenly and rapidly. The inner part of the grain is changed 

 to a gelatinous mass. The starch at the margin forms a thin, homogeneous ring, which rapidly 

 becomes thinner and transparent as the grain continues to swell. The swollen grains are large, 

 somewhat folded, and crumpled, but retain much of the original shape. 



Reaction with ferric chloride begins in 30 seconds and is over in 30 minutes. The hilum is verj' 

 prominent, often appearing as a dark bubble. The grains begin to gelatinize usually at the distal 

 end, with great and irregular protrusion; or gelatinization may begin at both ends. The process 

 extends completely around the margin, so that a ring of gelatinized starch surrounds a non-gelatin- 

 ized central portion. In the bean-shaped and reniform grains, however, the margin of the proximal 

 end is not affected until the hilum itself swells. After the peripheral portion has become gelatinized, 

 small pieces are broken, from time to time, from the non-gelatinized center, and gelatinize inde- 

 pendently until this part of the grain is completely dissolved. The swollen grains are very large, 

 greatly crumpled, lobulated, and distorted, and do not retain any of the original form. 



The reaction with Purdy's solution begins immediately in some of the grains, and one-third 

 are partially gelatinized and two-thirds completely gelatinized in 2 minutes. Both hilum and lamellae 

 become very distinct. The hilum swells and parts of the inner portion of the grain are dissolved, 

 but some of the starch appears to be forced unchanged to the margin, forming a ring which shows 

 fine striae and several very distinct, alternate refractive and non-refractive bands. This ring becomes 

 thinner and quite homogeneous and transparent as gelatinization proceeds and the grain swells, 

 until it forms a thin-walled capsule. The swollen grains are large, but not very much folded, wrin- 

 kled, or distorted. 



STARCH OF CHIONODOXA TMOLUSI. (Plate 36, figs. 213 and 214. Chart 145.) 



Histological Characteristics. — In form the grains are almost wholly simple, and they are isolated 

 with the exception of a few clumps. There are no pressure facets. The surface is often somewhat 

 irregular owing to uneven development, rounded protuberances, and nipple-like processes, the latter 

 being quite common. The conspicuous forms are ovoid, oval, lenticular, and clam-shell type; 

 also triangular, pyrifoim, round, ellipsoidal, reniform or bean-shaped, and various irregular forms. 

 The grains are usually not so thick as they are broad, and when seen on edge appear narrower at 

 the distal than at the proximal end. 



The hilum is rather small and usually not very distinct, but occasionally very prominent. 

 It is eccentric about one-fifth to two-fifths of the longitudinal axis of the grain, and may or may not 



