GENUS 8PREKELIA. 



643 



tened at one or more points. There are also pyriform, broadly triangular with curved base and 

 rounded angles approaching the clam-shell-shaped, dome-shaped, club-shaped, finger-shaped, len- 

 ticular, and almost quadrangular grains. The aggregates commonly occur as doublets of small or 

 medium-sized components of about eq\ial size, but sometimes they consist of one small component. 



The hilum may be observed as either a clear, round or lenticular spot which is eccentric, rang- 

 ing from slightly to one-fourth eccentric of the longitudinal axis. A small cavity from which two 

 short fissures radiate is frequently foimd at the hilum. The hilum is often fissured either by a trans- 

 verse cleft, by two clefts which form a cross, by a thorn-shaped cleft, or by a group of fissures form- 

 ing a stellate figure. 



The lamellce are usually not demonstrable throughout the entire grain. One and sometimes two 

 rather coarse and refractive lamellae frequently appear to divide the lamellae into groups of slightly 

 different character. The lamellae are generally not distinguishable directly around the hilum. Toward 

 the distal end they follow the outline of the grain. The number can not be satisfactorily determined. 



The grains vary in size; the smaller are 4 by Zft; the larger are 42 by 2S>n in length and breadth. 

 The common size is 26 by 20^ in length and breadth. There are laterally extended grains, the 

 larger of which are 28 by 38;u in length and breadth. The 

 common size of these is 20 by 28;u in length and breadth. 



Polariscopic Properties. — The figure may be slightly 

 to quite eccentric, of the leguminous type, or centric. Its 

 lines are rather fine and are sometimes straight, but often 

 bent or bisected. Double figures are also observed. 



The degree of polarization is high. The grains vary 

 from fair to very high, with the average high, often with a 

 variation in the same and different aspect of a given grain. 



With selenite the quadrants are fairly well defined 

 and usually irregular in shape and unequal in size. The 

 blue is more often pure, although in some grains it has 

 a greenish and in others a purplish tint. The yellow is 

 frequently not pure throughout the entire quadrants. 



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

 tion the grains color a fairly deep reddish-violet at once, 

 which deepens rapidly; with 0.125 per cent solution they 

 color a light red-violet, which deepens gradually. When 

 the grains are heated in water until all are gelatinized, the 

 solution colors a deep indigo-blue and the grains a light 

 blue, some with reddish tint, on the addition of iodine. When the preparation is boiled for 2 min- 

 utes and then treated with iodine the solution becomes a very deep indigo-blue and the grain-residues 

 a fairly deep, bright blue. When an excess of iodine is added the grain-residues become deep blue, 

 many with a reddish tint, and the capsules a deep red-violet to wine-red. 



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

 they are fairly well colored. 



With safranin the grains begin to stain at once and in 30 minutes they are fairly deep in color, 

 deeper than with gentian violet. 



Temperature Reaction. — The temperature of gelatinization is 76° to 78° C, mean 77°. 



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

 few grains are gelatinized in a minute, nearly all in 5 minutes, and all but rare resistant grains in 

 10 minutes, in which latter the reaction may take 30 minutes for completion. The grains color a 

 light red-violet at once, which deepens rather quickly to a deep old-rose and later to wine-red. 

 Either a dark ring or an irregular structure appears at the hilum, and gelatinization accompanied 

 by a dark reddish-purple coloration begins around the margin, spreading gradually towards the 

 center, accompanied by uniform swelling. During this process the ring or irregular structure at 

 the hilum enlarges and finally breaks. In the most resistant grains this structure persists for a long 

 time. The gelatinized grains are uniformly swollen and colored a deep reddish-purple. 



Reaction with chromic add begins in 30 seconds. A few grains are dissolved in 2 minutes, 

 nearly all in 7 minutes, and all in 10 minutes. The hilum or structures located here swell, the 

 lamellae become sharply defined and striated. Usually an internal longitudinal fissure with lateral 



