GENUS CANNA. 799 



Polariscopic Properties. — The figure is very eccentric and clear-cut. The lines are very broad 

 and do not vary much in breadth. Usually only one or two lines are visible throughout their course. 

 If one, it is in or near the longitudinal axis; if two, they run obUquely from the hilum. The lines are 

 not distorted and are placed at less varying angles to one another than in C. warszemczii. 



The degree of polarization is very high. Polarization colors may be seen in some grains. It is 

 higher and the colors are more visible when the grains are viewed on end or edge, and higher than 

 in the grains of C. warszemczii. 



With selenite the quadrants are fairly well defined, fairly regular in form, unequal in size. The 

 colors are very pure. 



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

 with 0.125 per cent solution the grains color at once and the color deepens rapidly. The color is 

 deeper than that of C. warszewiczii. After heating in water until the grains are completely gelati- 

 nized, the solution becomes a deep indigo color and the color of the grains varies from deep indigo 

 to a very faint tint upon the addition of iodine. After boiling for 2 minutes, the solution is colored 

 very deeply and the grain-residues very little. With a slight excess of iodine all the capsules are 

 of a red-violet color. 



Staining Reactions. — With gentian violet the grains begin to stain at once, the margins being 

 first affected, and in 30 minutes they are deeply stained, a few more deeply than the rest. The 

 stain is about the same as that of C. warszewiczii. 



With safranin the grains begin to stain deeply at once, and in 30 minutes are very deeply stained, 

 some much more than others. The stain is not so deep as that of the grains of C. warszewiczii. 



Temperature Reaction. — The temperature of gelatinization is 69° to 70° C, mean 69.5°. 



Effects of Various Reagents. — With chloral hydrate-iodine the grains begin to react in a minute; 

 about half are swollen in 5 minutes and the reaction is complete in 15 minutes. The hilum and the 

 lamellae are rendered indistinct. Then the hilum grows prominent as a black spot. In the mean- 

 time, the grains become colored a light violet, the distal end staining more deeply than the other. 

 The inner portion of the grain becomes lighter and the margin darker, the dark coloration of the 

 latter extending to the projections in the regions of the hilum, which begin to protrude, followed by 

 protrusion of other nearby portions. The hilum may now either darken and swell suddenly, or 

 gradually be included in the general swelling. The final result of the coloring and swelling is the 

 formation of masses characterized by an unswollen violet-colored center surrounded by a gelatinized 

 indigo-blue mass. As the reaction proceeds, the central portion swells in common with the rest of 

 the mass and becomes a deep blue, and darker than the surrounding parts. 



The grains begin to react in 30 minutes with chromic acid, and the reaction is complete in 3 

 minutes. Both hilum and lamellse become more distinct. Then, as the hilum begins to swell, 

 fine strise radiate from this point and the lamellae are obscm^ed. The proximal end of the grain 

 is dissolved, leaving a clear, open space. At the distal end lamellation again becomes distinct 

 and more and more marked until there occurs a spUtting off serially of several concentiic portions. 

 The main body of the grain in the meantime becomes clearer and finally disappears. If the 

 first crescent does not separate, the whole grain will after a time open out from the proximal 

 end and dissolve. 



With pyrogallic acid swelling of the grain begins in 2 minutes. One or two grains are entirely 

 swollen and the rest are in all stages of the reaction in 16 minutes, but the reaction does not progress 

 any further. The hilum swells slightly and protrudes. Two fissures on either side of the hilum 

 partially divide the grain, then many fine striae appear which radiate from the hilum, and deep 

 fissuration occurs in four or five directions attended by great swelling of the hilum; or vertical 

 fissuration may occur more or less irregularly without great swelling of the hilum, the parts so 

 defined swelling independently of one another, forming a very large, irregularly lobulated mass. This 

 form of swelling seems to be peculiar to the large ovoid grains. The gelatinized clam-shell and 

 reniform grains have a lamellated, somewhat rounded form, except at the point corresponding to 

 the location of the hilum, where the mass is clear and not so much crumpled and protruding. 



The reaction with ferric chloride begins in 13^ minutes and is complete in 10 minutes. It is 

 similar qualitatively to that of C. warszewiczii. 



Reaction with Purdy's solution begins in 15 seconds and is complete in almost all the grains 

 in IJ^ minutes and in all in 5 minutes. It is quahtatively the same as that of the grains of C. 

 warszemczii. 



