GENUS HYMENOCALLIS. 



647 



Chart No. 218. 



side of the distal end of an ovoid grain, slight shifting of the longitudinal axis of the lamellae; or 

 rarely to a secondary deposit of lamella? placed at right angles to the primary set. The conspicuous 

 forms are ovoid, ellipsoidal, nearly round, dome-shaped, ellipsoidal with squared distal end, and 

 bean-shaped; also rounded triangular and quadrangular, lenticular, bcll-jar-shaped, finger-shaped, 

 miissel-shell-shaped, and polygonal grains. 



There is usually either a small rounded cavity or a cleft at the hilum, but the hilum may be 

 observed as a clear, round, or elliptical spot which maj^ be centric, but is usuallj^ eccentric, frequently 

 eccentric about two-fifths, rarely one-third to one-sixth, of the longitudinal axis. The clefts fre- 

 quently appear diagonal to the longitudinal axis of the grain, which position is probably caused 

 by the slight shifting of the axis of the lamellae. Often one short transverse or diagonal cleft passes 

 just distal to the hilum or may intersect it. When two or more clefts are found they may be so 

 arranged as to form a cross, or a Y-shaped or fljang-bird figure. 



The lamella; are not distinct and are less clearly demonstrable near the hilum. On the large 

 grains one distinct and quite refractive lamella is usually found located at varying distances from 

 the hilum. On large grains occasionally 8 to 14 rather 

 coarse to fairlj- fine lamellae may be counted, which follow 

 the outline of the grain. 



The grains vary in size; the smaller are 3 by 2fi ; the 

 larger elongated grains arc 38 by 20iu, and the broadened 

 forms are 32 by 40m in length and breadth. The common 

 size is about 24 by 16^ in length and breadth. 



Polariscopic Properties. The figure may be eccentric, 

 centric, or of the bean type. Its lines are rather broad 

 and may intersect obliquely or at varying angles, but 

 sometimes they are in the form of a single, elongated, 

 mesial line with bisected ends, of the bean type; they may 

 be straight, but are often bent. 



The degree of polarization is high. The grains vary 

 from high to very high, but the proportion of the latter is 

 not great. There may also be some variation in the same 

 aspect of a given grain. 



With selenite the quadrants are well defined and 

 sometimes regular in shape and equal in size, but more 

 often they are irregular in shape and unequal in size. The 

 colors are generally pure, but sometimes either the yellow is not pure throughout the entire quad- 

 rants, or both the blue and the yellow may have a greenish tint. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains color a rather deep blue- 

 violet, which deepens rapidly; \\ith 0.125 per cent they color a light blue-violet which deepens 

 rapidly. After heating the grains in water until all are gelatinized and then adding iodine, the solu- 

 tion colors a deep indigo-blue and the grains a light to fairly deep bright blue. If the gelatinized 

 grains are boiled for 2 minutes and then treated with iodine, the grain-residues become a fairly 

 deep blue, many with a reddish tint, the capsules a deep reddish violet to heliotrope and the solu- 

 tion a very deep blue. With an excess of iodine the grain-residues color a deep, dull blue, many 

 with a reddish tint, and the capsules a deep heliotrope to a wine-red color. 



Staining Reactions. With gentian violet and with safranin the grains begin to color slightly 

 at once and in 30 minutes they are slightly colored. 



Temperature Reaction. The temperature of gelatinization is 70 to 72 C, mean 71. 



Effects of Various Reagents. With chloral hijdrate-iodiiie reaction begins immediately. About one- 

 third are gelatinized in a minute, about two-thirds in 2 minutes, nearly all in 5 minutes, and all but 

 a few resistant grains in 7 minutes, in which latter the reaction is usually complete in 15 minutes, 

 rarely 20 minutes. The grains immediately take on an old-rose color, which usually deepens quickly 

 to wine-red color. The hilum or the clefts at this region swell, and a small bubble appears. Gelatin- 

 ization accompanied by a deep blue coloration begins at the distal end, spreads around the margin 

 of the grain, and then advances towards the region of the hilum, which is the last part of the grain 

 to react. When grains have pressure facets, or sharp corners, gelatinization begins at these points 

 and then proceeds as before stated. The gelatinized grain is uniformly swollen and deeply colored. 

 43 



Curve of Reaction-Intensities of Starch of 

 Hymenocallis undulata. 



