GENUS HiEMANTHtrS. 



645 



Chart No. 217. 



of lamcllse placed at varying angles to the primary set; to a slight sliifting of the longitudinal axis 

 of the lamellae with a resultant curvation at one end of the grain; or to protuberances at different 

 points on the grain which vary in form from small nipple-like to finger-shaped processes. The con- 

 spicuous forms are ellipsoidal, ovoid, elongated ovoid, bean-shaped, triangular with rounded angles, 

 pyriform, and lenticular; also club-shaped, napiform, rod-shaped with curved ends, imperfect quad- 

 rangular, T-shaped, boot-shaped, and indefinite shapes. 



The hilum is usually very indistinct, but when clearly made out it is a round or oval spot which 

 varies from centric to quite eccentric, ranging usually from about five-elevenths to one-seventh of 

 the longitudinal axis. The hilum is, as a rule, not fissured, and a small cavity is occasionally observed. 



The lamellcB are very indistinct and arc not demonstrable throughout the entire grain. Those 

 which can be determined follow the outline of the main body of the grain. Occasionally 8 to 

 10 rather coarse lamellae may be counted. 



The size varies; the smaller are 4 by 3;u; the larger 

 are 36 by 20^ in length and breadth. The common size 

 is about 22 by 14;u in length and breadth. 



Polariscopic Properties. The figure is centric to quite 

 eccentric, and also bean tj'pe. The lines vary from rather 

 fine to quite broad, and frequently cross each other ob- 

 liquely, and also may be arranged to form a mesial line 

 with bisected ends (bean type), or to intersect mostly at 

 right or nearly right angles; they are often bent. Double 

 figures both of the compound and the aggregate type 

 are observed. 



The degree of polarization is high, with considerable 

 variation in the different grains, the range being from fair 

 to quite high, with the great majority high. Variation is 

 also frequent in the same aspect of a given grain. 



With selenite the quadrants are fairly well defined, 

 usually unequal in size, and irregular in shape. The colors 

 may be pure, but are often not quite pure. 



Iodine Reactions. With 0.25 per cent Lugol's solu- 

 tion the grains color a fairly deep blue- violet, which deepens rapidly; with 0.125 per cent solution 

 they become a very light violet, which deepens rather rapidly. After heating in water until the grains 

 are gelatinized and then adding iodine the solution colors a rather deep indigo-blue and the gelat- 

 inized grains a bright, fairly deep blue, a few with reddish tint. If the grains are boiled for 2 

 minutes and then treated with iodine the grain-residues become a rather light blue with a reddish 

 tint, the capsules a fairly deep reddish-violet, and the solution a very deep blue. With an excess 

 of iodine the grain-residues become a deeper blue with redder tint and the capsules a deep old- 

 rose to a wine-red. 



Staining Reactions. With gentian violet the grains begin to color slightly at once and in 30 

 minutes are very lightly stained. 



With safranin the grains begin to color slightly at once and in 30 minutes are lightly stained. 



Temperature Reaction. The temperature of gelatinization is 79 to 81 C, mean 80. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins immediately. A few 

 grains are gelatinized in 30 seconds, more than half in 2 minutes, nearly all in 3 minutes, all but 

 rare resistant grains in 5 minutes, in which latter the reaction is usually complete in 8 minutes, 

 rarely not until 14 minutes. The grains at once color a deep old-rose, which deepens to a wine-red 

 in many grains. The hilum becomes distinct in some grains. Gelatinization accompanied with 

 the deep-bluish color begins either at the distal end or in the protuberances and spreads around the 

 margin, then advances towards the hilum, which region is the last to undergo gelatinization. The 

 gelatinized grains are uniformly swollen and deeply colored. 



The reaction with chromic acid begins immediately. A few grains are dissolved in 2 minutes, 

 more than half in 3 minutes, nearly all in 4 minutes, all but resistant portions of a few grains in 5 

 minutes, and all in 6}^ minutes. The hilum swells and either one large, ragged, mesial cleft extends 

 towards the distal end, or one from either end of the slightly eccentric or centric hilum which is often 

 found in ellipsoidal grains; and large branches pass to any prominent corners or protuberances on the 



