772 STARCHES OF MtJSACB^. 



With selenite the quadrants are not well defined, very unequal in size, and irregular in shape. 

 The colors are not pure. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains color immediately and very 

 deeply a bluish- violet; with 0.125 per cent solution they color immediately, and the color deepens 

 quickly. After heating in water until the grains are completely gelatinized, the solution colors 

 lightly but the grains deeply on the addition of iodine. If much iodine is added a violet-colored 

 capsule appears in some grains. After boiling for 2 minutes the solution is colored somewhat more 

 deeply, but the grain-residues slightly; with an excess of iodine the capsules are colored a ))lue-violet. 



Staining Reactions. With gentian violet staining begins in 30 seconds, but after 30 minutes 

 the grains are fairly deeply stained, some more than others. 



With safranin staining begins immediately, but at the end of 30 minutes the grains are only fairly 

 deeply stained, some more than others. This reaction is much less than that with gentian violet. 



Temperature Reaction. The temperature of gelatinization is 67 to 68.5 C, mean 67.75. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins in most grains in a 

 minute; in all in 3 minutes. Most grains darken in 5 minutes and all are darkened in 13 minutes. 

 The hilum is prominent and the lamellse are not obscured. If the grain is eroded, as is the case 

 with some in the preparation studied, there is swelling and protrusion from the various irregular 

 points about the margin. Swelling and protrusion usually begins at one or two points at the distal 

 end. These join and the process extends gradually upward over the whole grain. At times both 

 proximal and distal ends swell, followed by swelling of other parts of the grain; or very frequentlj- 

 the process extends upward around the margin from the distal end and stops on each side of the 

 hilum, until the other parts of the grain are gelatinized, and then the hilum swells; or the entire 

 margin may be gelatinized so that there is a ring of gelatinous material about the ungelatinized 

 central part of the grain. The gelatinized grains are small and show two or three or four long, 

 finger-like projections at the proximal end, and a number of dark lines or folds more or less completely 

 separated by light spaces at the distal end, arranged like the lamellse. 



The reaction ndth chromic acid begins in 30 seconds and is over in A}/n minutes. The grain is 

 divided by fine fissures, which rapidly grow coarse and more distinct. The hilum swells out in the 

 form of a long, narrow projection from the end of the grain. The jiroximal end is dissolved and 

 opens out. The rest of the grain becomes divided into rows of granules following the lines of the 

 lamellae, and these in turn are divided at the distal end into concentric crescents, one of which rarely 

 separates and is dissolved independently. The rest of the grain dissolves slowly, the upper portion 

 just beneath the swollen hilum, where the largest granules are, being the last to dissolve. 



With pyrogaUic acid the reaction begins in 30 seconds and is over in 45 minutes. The hilum 

 and lamellse are both distinct. The hilum swells slightly and two lines appear, one on each side, 

 which are like the hilum in appearance and widen out as the hilum swells. The hilum continues to 

 increase in size, or rather the inner portion of the grain is broken down into a finely granular, gelat- 

 inous mass. A slight line of resistant starch persists for a time at the margin, but soon clears awa}\ 

 The grain swells slowly and evenly. There are often formed two or tliree rows of coarse granules, 

 the gi-anulcs near the hilum being gelatinized last. When the reaction is complete the gelatinized 

 grains are large, somewhat folded and otherwise distorted. 



With ferric chloride the reaction begins in 23^2 minutes and is over in 10 minutes. The hilum 

 and lamellce are distinct and the margin becomes clear. Various points, especially at the distal 

 end, begin to gelatinize, and the process spreads towards the proximal end over the whole grain, 

 the swelling proceeding in succession from row to row. The hilum protrudes as a long, finger-like 

 projection, and usually before this process is complete similar protrusions occur at two or three 

 nearby points. The gelatinized grains formed during the process show an irregular, sacculated 

 appearance at the proximal end and a somewhat irregular margin with the inner portion laid in 

 folds which follow the lines of lamellse. 



The reaction with Purdy's solution begins immediately and is over in 4 minutes. A few grains 

 are probably not completely gelatinized even at the end of an hour or more. The hikun and lamellse 

 are made very distinct. The hilum swells somewhat, often without any saccular protrusion. The 

 inner portion of the grain is divided into rows of granules by fine strite and by transverse fissures 

 which follow the lines of the more prominent, non-refractive lamellse. These granules are converted 

 into a clear, gelatinous, finely granular mass as the grain swells slowly and evenly. The gelatinized 

 grain is large and shows folds in the lower part corresponding to the lines of lamellse. It maj^ or may 



