392 STABCHES OF LEGUMINOS^. 



Stnining Reactions. With gentian violet and with safranin the grains all begin to stain very 

 lightly at once and in 30 minutes are still lightly stained. 



Temperature Reaction. The temj^crature of gelatinization is 79 to 80 C, mean 79.5. 



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

 45 seconds. It is complete in aliout one-fifteenth in 5 minutes, in about one-fourth in 15 minutes, in 

 half in 30 minutes, and in about seven-eighths in an hour. The lamelli3e become more sharply defined, 

 and the hilum, or the cleft, at this region swells and often becomes very irregular in outline. Gelatini- 

 zation begins at the distal end and proceeds graduallj' over the grain, accompanied by uniform swell- 

 ing. The gelatinized starch at the distal end colors a deep blue and the remainder of the grain an 

 old-rose color. During gelatinization the blue coloration sweeps towards the proximal end, obscuring 

 the cleft at this point. Finally the entire grain is gelatinized and deeply colored. Sometimes the gela- 

 tinized portion of the grain is sharply differentiated from the ungelatinized, and as the reaction pro- 

 ceeds towards the proximal end, the blue-colored starch pushes before it a colorless, imgclatinized mass. 

 The gelatinized grain is much swollen, but retains the shape of the untreated grain. The color is a 

 deep blue with light areas which correspond with the positions of the clefts in the normal grains. 



Reaction with chromic add begins immediately. A few are dissolved in 2 minutes, all but a 

 few resistant grains in 5 minutes, and all in 7 minutes. The hilum, or the cleft at this point, swells, 

 and frequently a bubble is formed which enlarges and then suddenly collapses. The lamellse become 

 very sharply defined and striated. Longitudinal branched fissures, if not already present, are formed 

 and extend obliquely from the region of the hilum towards the distal margin. Solution of the grain 

 occurs first around the hilum and proximal end, and then advances between the fissures, many 

 refractive particles resisting the reaction for some time. During gelatinization the grain often 

 swells slowly and uniformly until it has become a large, clear, ellipsoidal body before the capsule 

 rujjtures at the proximal end, when the extruded mass and the capsule pass into solution. The 

 lamella' at the distal margin and for a short distance at the sides of the grain are the last to be 

 gelatinized, and frequently appear as a transient, serrated, inner lining of the capsule. The starch at 

 the distal end may be so resistant that it remains after the rupturing at the proximal end and the 

 outflow of the semi-liquid gelatinized starch, but it soon disappears. 



The reaction with pyrogcdlic acid begins in a few grains in 30 seconds. It is complete in a few 

 in 2J^ minutes, in about two-thirds in 5 minutes, in nine-tenths in 10 minutes, and in all but a few 

 very resistant grains in 15 minutes. The latter may show very little effect, even after treatment 

 for an hour. The hilum or the cleft located at this point begins to swell and a bubble often appears 

 which is expelled before general gelatinization begins. If not already present, two main, longitu- 

 dinal, branched fissures are formed which pass obliquely from the hilum towards the distal margin. 

 The lamelhe become very sharply defined and striated, gelatinization begins at the region of the 

 hilum, and the lamella; at the proximal end are gelatinized. As the starch is gelatinized along the 

 fissures the lamella; are often affected in such a manner as to form a serrated lining to the capsule. 

 During the gelatinization of the lamella? refractive bodies remain which are often arranged irregu- 

 larly, but sometimes in a row, at about the region of the highly refractive lamella which is found 

 on some grains. Usually some of the lamella; remain at the distal end. If the fissures are very deep, 

 the grain is sometimes divided into two parts, which may separate at one or both ends of the cleft; 

 the lamellse are thrown into folds in which the refractive bodies are collected. The gelatinized grain 

 is much swollen and distorted. 



Gelatinization with /erne chloride begins in a small number of grains in 33^^ minutes. A few are 

 gelatinized in 10 minutes, about one-sixth in 30 minutes, and about one-fifth in an hour. A narrow 

 border of gelatinized starch is formed, the hilum or the cleft at this region begins to swell, and the 

 lamelkc become sharply defined and striated. Eadiating fissures, if not already present, are formed 

 and pass from the hilum or cleft at that region towards the distal end; and delicate fissures are 

 also formed which pass through the lamellae at the distal end. Gelatinization with distension of 

 the capsule usually starts at one end and may spread gradually over the grain, and a similar swelling 

 appears at the opposite end and spreads in the opposite direction. During the reaction small par- 

 ticles are detached from the main body of the grain and gelatinizetl separately, and near the com- 

 pletion of the process the most resistant starch is separated forcibly into two or three rather large 

 fragments, which are finally gelatinized. The gelatinized grains are much swollen and distorted. 



The reaction with Purdy's solution begins in a few grains in 1 3^ minutes and only gradual changes 

 are noted for about 30 minutes, at which time the central portion of only about one-tenth of the 



