660 STARCHES OP AMARYLLIDACEiE. 



ponent grains of the aggregates are in this process made very distinct by light lines. The component 

 grains swell at the margin, and the grain as a whole gradually becomes gelatinized. The grains which 

 constitute an aggregate swell to variable degrees, and when all are gelatinized the mass resembles a 

 mulberry in form. In the linear aggregates and compounds the components at both ends react, thus 

 presenting the appearance of bipolar swelling. The gelatinized grains are not much larger than the 

 original grains and appear to consist of two parts, an outer wall which is light in color and shows 

 folds and creases, and an inner part which is dark and irregularly fissured. 



Reaction with chromic acid begins in a few seconds and is over in 30 seconds. The hilum be- 

 comes very distinct; it appears as a light, refractive spot when not fissured and as a dark bubble 

 when fissured. As the hilum swells the bubble disappears. The hila in all aggregates and compounds 

 apparently swell at the same time. All of the component grains swell enormously and rapidly; 

 the margin of the grain becomes very distinct as a striated and distinctly banded ring. The whole 

 grain becomes clearer, and finally one point on the margin is dissolved, followed rapidly by solution 

 of other parts. The aggregates often open centrally to form a ring of swollen grains which finally 

 disappear. 



The reaction with pyrogallic add begins in 20 seconds and is over in 2J^ minutes. The hilum 

 becomes very distinct and also the lines showing the boundaries of the component grains of com- 

 pounds; but the lamellae are invisible. The hilum swells rapidly and considerably, pushing out the 

 walls of the grain into a thick, finely striated, and indistinctly banded ring. After the reaction is 

 complete the aggregates and compounds often have a mulberry-like appearance, composed of sep- 

 arate, clear, gelatinized grains, not much folded or crumpled. The individual component grains 

 are usually spherical or slightly oval, and not much distorted. 



The reaction with ferric chloride begins in 30 seconds and all the grains are gelatinized in 15 

 minutes. The hilum is distinct as a black spot or bubble. The marginal part of the single grain 

 becomes clear and darker, causing the central part to appear lighter and opaque. Portions of the 

 margin begin to gelatinize and to protrude irregularly, and this process extends all the way around 

 the margin. The hilum suddenly swells, pushing out parts of the grain in all directions. A dense 

 band is formed at the margin which quickly clears, and with the formation is a large, crumpled 

 and folded gelatinized grain. In the compounds and aggregates the component parts swell unevenly, 

 and the gelatinized grains are lobulated, folded, and crumpled. Often the central portions of some 

 of the grains remain ungelatinized. 



Reaction with Purdy's solution begins at once and is over in 30 seconds. The hilum becomes 

 very distinct, either as a refractive spot or a dark bubble. The lamellae are fairly distinct. The 

 hilum swells enormously, pushing the substance of the grain out peripherally, the margin becoming 

 striated and occasionally banded. The gelatinized grains formed from the simple grains are large, 

 round, or oval, and not cnmipled or folded; but those formed from compounds and aggregates are 

 usually in the form of large, lobulated, mulberry-like masses. 



STARCH OF ALSTR(EMERIA BRASILIENSIS. (Plate 57, figs. 339 and 340. Chart 225.) 



Histological Characteristics. — In form the grains are usually simple, with a very few compound 

 grains. Neither aggregates nor grains with pressure facets were observed, nor clumps. The surface 

 of the grains is quite regular, the projections and depressions being quite small. The conspicuous 

 forms are the ovoid, spherical, and oval to elliptical. The grains are not flattened, and appear 

 round when seen on end. 



The hilum is a fairly distinct, small, round spot, eccentric from two-fifths to one-sixth, usually 

 one-fifth, of the longitudinal axis of the grain, and in or much to one side of the median line. The 

 hilum may be double or multiple, and the multiple hila are usually arranged irregularly in a small, 

 non-lamellated space. The hilum may be fissured, and the fissure is usually small but deep, trans- 

 verse or diagonal, clean-cut or ragged; or there may be two or more fissures variously arranged. 

 Fissuration in these grains is not conspicuous, as also in A. ligtu, and in marked contrast with the 

 decidedly fissured grains of A. aurantiaca (aurea). 



The lamellcB are, as a rule, not very distinct, and are rather fine, regular circles or segments of 

 circles, which are probably continuous and which some distance from the hilum tend to follow 

 closely the outline of the margin of the grain. They are finer, more distinct, and circular near the 

 hilum. There are 18 to 24 on the larger grains. 



The grains vary in size from 10 to 48p. The common size is 30/i. 



