GENUS JATKOPHA. 875 



The degree of polarization is very high. It is higher when the grain is seen on end and varies 

 in the same aspect of a grain; it is low over some of the facets. 



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

 are pure. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color deeply a blue-violet; 

 with 0.125 per cent solution they tint readily. After heating in water until all the grains are com- 

 pletely gelatinized, the solution colors lightly and the grains deeply with iodine. The grains are 

 folded, crumpled, and much distorted. After boiling for 2 minutes the solution is deeply colored, 

 but the grain-residues much less. With excess of iodine the capsules become a dark violet. 



Staining Reactions. — With gentian violet the grains tint slightly in IJ/^ minutes and after 15 

 minutes show a fairly deep color; all appear to stain with equal readiness. 



With safranin the grains tint slightly in a minute and at the end of 15 minutes show a fairly 

 deep color. 



Temperature Reaction. — The temperature of gelatinization is 59" to 60° C, mean 59.5°. 



Effects of Various Reagents. — With chloral hydrate<odine reaction begins in 30 seconds. Almost 

 all the grains are fully swollen in 10 minutes, but a few remain only partly swollen after an hour. 

 The hilum and lamellae are rendered distinct. The hilum appears a.s a dark spot or bubble. Gelat- 

 inization begins at the lines bordering the facets, with considerable protrusion, causing a fringe- 

 like projection around each facet. Occasionally the proximal end also begins to gelatinize. If 

 the grain has a long, transverse diameter, the ends corresponding to this diameter may darken and 

 occasionally gelatinization will extend all around the margin; but usually the process extends 

 from the distal end and finally includes the whole grain. The gelatinized grains are large, but 

 not much distorted, and they show either an inner clear space surrounded by a dark marginal band 

 or an inner dark mass surrounded by a lighter area, which latter is in turn surrounded by a dark 

 marginal band. 



Reaction with chromic acid begins in 20 seconds and is over in 45 seconds. The hihim swells 

 very rapidly, forcing the substance of the grain out to the margin, which becomes more distinct. 

 The margin is thick and shows finely striated, alternate refractive and non-refractive bands. The 

 grain swells greatly and becomes lighter and more transparent, and finally one point in the marginal 

 band or capsule is dissolved and the contents are extruded, the remainder of the marginal band 

 finally disappearing in solution. 



The reaction with pyrogallic acid begins in 30 seconds and is over in 2 minutes. The hilum 

 becomes very distinct and is often marked by a dark bubble. It swells rapidly, as does the rest of 

 the grain, especially the comers and lines of anion of the facets, while the facet surfaces appear to 

 become hollow. The substance of the grains is pushed out to form a wide, finely striated ring, 

 which occasionally shows refractive and non-refractive bands. This ring becomes thinner and more 

 transparent as the grain is gelatinized. The gelatinized grains are large, ovoid, or rounded, and 

 somewhat distorted and folded at the faceted ends. 



The reaction with ferric chloride begins in a minute. It is over in four-fifths in 5 minutes and 

 in all in 16 minutes. The hilum is fairly distinct, but the lamellae are indistinct. Gelatinization with 

 some irregular protrusion first occurs at the edges of the facets. It occurs occasionally at both 

 ends and may extend over the greater part of the grain before the hilum assumes a bubble-like ap- 

 pearance, and then suddenly swells to a great size, the bubble in the meantime disappearing. The 

 portion of the grain still ungelatinized is pushed out to the margin, which appears as a wide, finely 

 striated line partly surrounding a clear space. The gelatinized grains are large ovoid with a clear 

 space representing the swollen hilum, which is elongated and narrow, and with a lobulated and 

 crumpled appearance at the end where gelatinization began. 



Reaction with Purdy's solution begins in 20 seconds and is practically over in 3 minutes, 

 although a few grains are not completely swollen until 15 minutes have passed. The hilum swells 

 enormously, pushing the substance of the grain out to form a narrow but very distinct marginal 

 ring with clearly defined, striated, alternately refractive and non-refractive bands. There is a row 

 of coarse granules just inside this ring. The grain continues to swell slightly and the band becomes 

 clearer and thinner. There is formed a large, ovoid gelatinized mass, slightly folded and crumpled 

 at the faceted end, at which there may be a granular mass which disappears in time. The gelatinized 

 grains are fairly regular in outline and not much distorted. 



