IRIS. 



657 



With selcnite the quadrants are moderately clear- 

 cut. They are unequal in size and often very irregular in 

 shape. The colors are usually not pure, the yellow being 

 more often impure than the blue. 



Comparison of the polariscopic properties between 

 7. cengialti and /. pallida queen of may shows: 



The figure is more distinct and well defined than in 

 /. pallida queen of may. The lines cross at a right angle 

 or at an acute angle which varies much more widely in 

 size in different grains than in I. pallida queen of may. 

 They are also less often bent and bisected than in that 

 starch. The figure is less often in the form of a conju- 

 gate hyperbola or of a long line bisected at both ends. 



The degree of polarization is (60) 10 units higher 

 than in /. pallida queen of may, as there are more grains 

 in which it is moderately high to high than in that 

 starch. There is less variation in a given aspect of the 

 same grain. 



With sclenife the quadrants are more clear-cut and 

 less irregular in form than in I. pallida queen of may. 

 The colors are also more often pure than in that starch. 



IODINE REACTIONS. 



With 0.25 per cent Lugol's solution the grains all 

 color a light to moderate violet tinged with blue (value 

 35). The color deepens with moderate rapidity until it is 

 very deep, at the same time assuming more of a bluish 

 tint. With 0.125 per cent Lugol's solution the grains 

 all color a very light violet. The color deepens with 

 moderate rapidity until it is deep, and has assumed a 

 bluish tint. After heating in water until all the grains 

 are completely gelatinized and then treating with a 2 

 per cent Lugol's solution, the gelatinized grains all color 

 a moderate, moderately deep, or deep indigo, and the 

 solution a deep indigo. If the preparation is boiled for 

 2 minutes and then treated with a 2 per cent Lugol's 

 solution, most of the grain-residues color a very light 

 indigo; the capsules a deep wine-red; and the solution 

 a very deep indigo. 



Comparison of the iodine reactions between I. cen- 

 gialti and /. pallida queen of may shows : 



With 0.25 per cent Lugol's solution the grains are 

 colored a moderate violet tinged with blue (value 45), 

 5 units more than in I. pallida queen of may. With 

 0.125 per cent Lugol's solution the grains all color a 

 light violet more than in I. pallida queen of may. After 

 heating in water until the grains are all gelatinized and 

 then treating with a 2 per cent Lugol's solution, the 

 gelatinized grains all color a moderate indigo, less than 

 in I. pallida queen of may; and the solution a very deep 

 indigo, more than in /. pallida queen of may. If the 

 preparation is boiled for 2 minutes and then treated 

 with a 2 per cent Lugol's solution, the grain-residues 

 are colored a light to moderately light indigo, more than 

 in I. pallida queen of may; the capsules a reddish violet 

 instead of a deep wine-red as in I. pallida queen of may; 

 and the solution a very deep indigo as in /. pallida 

 queen of may. 



ANILINE REACTIONS. 



With gentian violet the grains all color very lightly 

 at once, and in 30 minutes they are moderately colored 

 (value 48). Many of the grains are moderately deeply 

 colored but the majority are light to moderately colored. 



With safranin the grains all color very lightly at once, 

 and in 30 minutes they are moderately colored (value 

 52) more than with gentian violet. Many of the grains 

 are moderately deeply colored, but the majority are light 

 to moderately colored. 



Comparison of the aniline reactions between 7. cen- 

 gialli and 7. pallida queen of may shows : 



With gentian violet the grains are colored (value 

 45) 3 units less than in 7. pallida queen of may. 



With safranin the grains are colored (value 50) 2 

 units less than in 7. pallida queen of may. 



There is very little difference to be noted in the 

 reactions of the two starches with aniline stains. 



TEMPERATURE REACTIONS. 



The temperature of gelatinization of the majority of 

 the grains is 71 to 73 C., and of all is 75 to 75.8 C., 

 mean 75.4 C. 



Comparison of the temperature reactions between 

 7. cengialti and 7. pallida queen of may shows : 



The temperature of gelatinization is 74 to 76 C., 

 mean 75 C. The temperature of gelatiuization of the 

 majority of the grains of I. pallida queen of may is 1 C. 

 higher and of all of the grains 0.4 C. higher than that 

 of 7. cengialti. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins in 1 min- 

 ute. Complete gelatinizatiou occurs in about 4 per cent 

 of the entire number of grains and 10 per cent of the total 

 starch in 5 minutes; in about 50 per cent of the grains 

 and 55 per cent of the total starch in 15 minutes; in 

 about 68 per cent of the grains and 72 per cent of the 

 total starch in 30 minutes; in about 78 per cent of the 

 grains and 83 per cent of the total starch in 45 minutes; 

 in about 81 per cent of the grains and 84 per cent of the 

 total starch in 60 minutes. (Chart D 421.) 



The hilum becomes distinct, attended by the forma- 

 tion of a bubble in most of the grains. The lamellte are 

 usually not visible, but in some grains may be indis- 

 tinctly seen. The grains become more refractive after 

 the addition of the reagent, and the first part to show this 

 change is a rather narrow band of starch at the margin 

 which becomes moderately refractive. Gelatinizatiou be- 

 gins at the corners of the distal margin and spreads from 

 these points across the distal margin. Two longitudinal 

 fissures appear and extend about half the distance from 

 the distal margin to the hilum, and the portion marginal 

 to the fissures is more rapidly gelatinized than that com- 

 prehended between them. After the ends of the fissures 

 are passed in the progress of gelatinization the central 

 and marginal portions of the grain gelatinize with equal 

 rapidity. When the hilum is reached it swells suddenly 

 and rapidly, and the bubble if present swells also, then 

 shrinks, and finally disappears. The starch at the prox- 

 imal end which is the last to be gelatinized is gelatinized 

 rapidly after this swelling of the hilum. 



The gelatinized grains are much swollen, have rather 

 thick capsules, and are greatly distorted especially at 

 the distal end. 



Comparison of the chloral-hydrate reactions between 

 7. cengialti and 7. pallida queen of may shows : 



The hilum becomes distinct, attended by the forma- 

 tion of a bubble in a somewhat smaller majority of the 



