GENUS GE8NERIA. 887 



With selenite the quadrants are well defined, very irregular in shape, and unequal in size. The 

 colors are pure. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains are colored immediately 

 and very deeply a blue-violet; with 0.125 per cent solution they color deeply. After heating until 

 all the grains are completely gelatinized, they color very deeply and the solution very lightly with 

 iodine; some have a red-violet capsule. After boiling for 2 minutes the solution colors very deeply, 

 but the grain-residues very lightly. With a slight excess of iodine all the grains exhibit a deeply 

 colored red-violet capsule. Some of the capsules retain starch in the upper portion that colors a 

 faint blue. The capsules are much lobulated, twisted, and distorted, especially at the base. 



Staining Reactions. — With gentian violet the grains begin to stain at once. After 30 minutes 

 they are deeply and evenly stained. 



With safranin the grains begin to stain at once and after 30 minutes are fairly deeply and 

 evenly stained. 



Temperature Reaction. — The temperature of gelatinization is 64° to 65° C, mean 64.5°. 



Effects of Various Reagents. — With chloral hydrate-iodine the reaction begins in 30 to 60 seconds 

 and most of the grains are darkened in 5 minutes. All are gelatinous and swollen and the reaction 

 is complete in 15 minutes. The hilum usually becomes prominent, but not the lamellae. The grain 

 shows a dark spot at either the distal or the proximal end; this spot swells somewhat and the same 

 process occurs at the opposite end and from these two points gelatinization spreads over the whole 

 grain. There is usually a sharp line of demarcation between the swollen and unswoUen portions. 

 In the grains with secondary deposits which show a double base or distal end, the reaction begins 

 in the part last formed. In a few cases the reaction begins at but one end and spreads over the grains. 

 Usually the whole margin in such cases becomes darkened first, and then the inside of the grain. 

 After the whole grain is completely darkened, swelling continues for a short time. During this 

 reaction there is formed a comparatively large gelatinous ma.ss, the enlargement occurring partic- 

 ularly in a longitudinal direction. There is formed a very irregular base or distal end that is lobu- 

 lated and divided by light fissures; a round proximal end that has a round area surrounded by a 

 dark ring; and a middle portion which may be homogeneously dark, but is usually crossed by one 

 or two light fissures separating the dark mass into more or less irregular bands. The gelatinized 

 grains retain some of the original shapes of the grains. There is often a wide, light space between 

 the original grain and the added portion. 



The reaction with chromic acid is general in 30 seconds and is over in 5 minutes. The hilum 

 becomes prominent, but not the lamellae. Two lines or fissures extend downward, one on each side 

 of the hilum. The portion included by these fissures becomes lighter in color and is quickly broken 

 up by other irregular fissures. The hilum swells, the swelling extending especially upward; the 

 inner portion of the grain, which is irregularly granular, breaks down into a gelatinous mass. The 

 more resistant starch at the margin appears as a rather thin ring, ragged on the inner edge and di- 

 vided by fissures into a row of granules. This ring soon becomes a thin transparent coating which 

 iuvaginates at one side. It dissolves either at the top or at the side, and the inner liquefied starch 

 flows out and is dissolved, followed by a solution of the rest of the margin. 



With pyrogallic acid there is a very slight general reaction in. \}/2 minutes. The majority of 

 the grains are fully gelatinized in 15 minutes and all in 30 minutes. Both the hilum and lamellae 

 become very prominent. The hilum enlarges somewhat and two lines or fissures extend downward 

 from the hilum, one on each side. The portion included between them becomes more transparent, 

 the lamellae fade away, and the grain presents a striated appearance, the striae extending upward 

 from the base. The proximal end enlarges rapidly as the hilum continues to swell. There is here 

 a rather thin, homogeneous-looking band. The inner lower portion also finally passes into a gelat- 

 inous mass, leaving the margin very irregularly lobulated and folded. The margin becomes clearer 

 and more transparent until finally a thin-walled mass is formed. This gelatinized grain is large 

 and does not retain much if any of the original form. It is rounded and somewhat folded at the 

 proximal end and is very irregular at the distal end. 



There is a restricted reaction with ferric chloride in a few minutes, which becomes general in 

 3 minutes. Most grains are gelatinized in 6 minutes and all in 10 minutes. The hilum becomes 

 prominent, but not the lamellae. There are in general two methods by which the reaction may 

 start and proceed : The hilum may swell somewhat and two fissures extend, one on each side, into 

 the substance of the grain, the inclosed area becoming fissured from the base. The hilum continues 

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