GENUS MAEANTA. 825 



ovoid grains arc 30 by 16m, and of the siiell-shaped 28 by 24fi in length and breadth. The common 

 size is about 22 by 20/i in length and breadth. 



Polariscopic Properties. The figure is usually centric to slightly eccentric, rarely quite eccen- 

 tric. Its lines are distinct, usually straight, and rather fine, and cross each other at right angles, 

 rarely obliquely, and they may be bent. Compared with M. arundinacea the lines generally cross 

 each other at a different angle and are much less often bent. 



The degree of polarization is high, but slightly lower than in M. arundinacea. The same varia- 

 tion is found in the different grains, but the proportion in which polarization is very high is much 

 smaller. A similar variation is found in the same aspect of a given grain as that of M. arundinacea. 



With selenite the quadrants are distinct and clean-cut, and generally equal in size and regular in 

 shape. The colors are generally pure. The quadrants are as clean-cut and the purity of the colors 

 the same as in M. arundinacea, but they are commonly nearer equal in size and more regular in shape. 



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

 reddish-violet (about the same for both large and small grains), which deepens rapidly. The tint 

 is deeper, duller, and more reddish in some grains, and deepens more rapidly and with less variation 

 in intensity than in M. arundinacea. After heating in water until the grains are gelatinized and then 

 adding iodine, the solution becomes blue, somewhat lighter than in M. arundinacea, and the large 

 grains a lighter, somewhat brighter blue than those of M. arundinacea; and some of the small grains 

 a light blue, many with reddish tint to red-violet. The blue is lighter, and those with reddish tint 

 are somewhat redder than in M. arundinacea. If the gelatinized grains are boiled for 2 minutes 

 and then treated with iodine, the solution colors a very deep blue and the grain-residues of the small 

 grains a light old-rose, those of the large grains a deep blue with reddish tint to red-violet. With 

 an excess of iodine the capsules color a deep old-rose to a wine-red; the color is deeper and redder 

 than in M. arundinacea. 



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

 minutes are very lightly stained, the large scattered grains a little deeper than the others, but all 

 distinctly lighter than in M. arundinacea. 



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

 the larger ones somewhat deeper than the others, but all distinctly lighter than in M. arundinacea. 



Temperature Reaction. The temperature of gelatinization for the small grains is 73 to 75 C, 

 mean 74. Several scattered, large grains are gelatinized at 78 to 80 C, mean 79; but others 

 are unaffected at this temperature. The scarcity of material in this preparation and the effect of 

 very high temperature upon the smaller grains in the solution prevented carrying it fm-ther. In view 

 of the resistance of these large, scattered grains to some of the chemical reagents, it is probable 

 that the majority are not gelatinized until a higher temperature is reached than the above. 



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

 grains are gelatinized in 30 seconds, nearly all in l}4 minutes, all but a few resistant in 2 minutes, 

 and these latter usually in 4 to rarely 11 minutes. The most resistant grains are the rather large, 

 mussel-shell-shaped type; some of these large grains, however, are gelatinized in 2 minutes, and 

 since they are very few it is difficult to form conclusions as to their rate of gelatinization. The 

 reaction is qualitatively the same as in M. arundinacea with the following exceptions: First, the 

 grains color a deeper old-rose at once; second, in the few large grains under observation the last 

 region of the grain to become gelatinized is distal to the hilum, and thus nearer the center of the 

 grain. The gelatinized grain is uniformly swollen and thus retains the shape of the untreated grain. 



Reaction begins at once with chromic add. Several grains are gelatinized in a minute, nearly 

 all in 1}/^ minutes, and all but rare resistant grains in 2 minutes, in which the reaction is usually 

 completed in 43^, rarely 6}4 minutes. The most resistant grains are the scattered shell-shaped, 

 triangular, and ovoid forms. The reaction is qualitatively the same as in M. arundinacea with the 

 follomng exceptions: First, no bubble was observed at the hilum and the refractive granules which 

 appear at the region surrounding it during gelatinization are more briUiant. Second, since most 

 grains differ so much in shape the arrangements of the fissures are very often not the same; one 

 radiating fissm-e passes from each side of the hilum to the corners of the distal margin of dome-shaped 

 grains, the capsule ruptures at one of these points and the sides and proximal end are dissolved 

 before the distal margin. Third, in the few large grains under observation, no bubble was foimd at 

 the hilum and the capsule ruptured at one side near the proximal end, the lamellae were more sharply 

 defined, and when disorganized the refractive granules were more brilliant. 



