GENUS SCIIiLA. 



543 



Chart No. 142. 



GV S T CI CA PA FC T» S CI PA CA 



The grains vary in size from 6 to 46/.«. The common size is 32ju. The dimensions of an average 

 rounded ovoid grain are 32 by 26;u in length and breadth. 



Polariscopic Properties. — The figure is usually eccentric, distinct, and generally clear-cut. Its 

 rather broad lines become broader and less well defined in many grains, especially the longer lines, 

 when Hearing the margin. The lines may be bent and otherwise distorted, vary in width, and be 

 placed at varying angles with each other. 



The degree of polarization is high. It may be less towards the margin. It is much higher than 

 that of the grains of S. siMrica. It does not vary greatly in different grains nor in different aspects 

 of the same grain. 



With selenite the quadrants are fairly clear-cut, usually unequal in size, and generally regular 

 in form. The colors are fairly pure. As a rule the blue shows an admixture of yellow. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains are deeply colored a blue- 

 violet at once; with 0.125 per cent solution they color at once slightly and the color deepens slowly. 

 The coloration is not so deep as that of the grains of (S. 

 sibirica. After heating until all the grains are completely 

 gelatinized, the solution is colored lightly and the gelat- 

 inized grains very deeply with iodine. After boiling for 

 2 minutes the solution is colored very deeply, but the 

 grain-residues lightly. With an excess of iodine the cap- 

 sules take on a violet color. 



Staining Reactions.— With gentian violet the grains 

 begin to stain at once, especially about the margin. After 

 30 minutes they are fairly stained, some more than others. 

 The shade is slightly deeper than that of the grains of 

 S. sibirica. 



With safranin the grains begin to stain evenly at 

 once. After 30 minutes they are fairly deeply colored, 

 some more than others. The shade is nearly the same, 

 but probably somewhat deeper, on the whole, than that 

 of the grains of »S. sibirica. 



Temperature Reaction. — The temperature of gelatin- 

 ization is 65° to 66° C, mean 65.5°. 



Effects of Various Reagents. — With chloral hydrate- 

 iodine the reaction begins in 30 seconds. About half are darkened in 3J^ minutes and all but a few are 

 gelatinized in 15 minutes. The reaction proceeds without much swelling until the portion containing 

 the hilum is involved. This reaction is qualitatively the same as that of the grains of S. sibirica. 



With chromic acid some grains begin to react immediately. All are affected in 30 seconds, and the 

 reaction is over in 2 minutes. The reaction is qualitatively the same as that of the grains of <S. sibirica. 



With pyrogallic acid there is a shght general reaction immediately. A few are partially gelatin- 

 ized at once. Nearly all are gelatinized in 40 seconds and all in 65 seconds. The reaction is quali- 

 tatively the same as that of the grains of S. sibirica. 



Reaction with ferric chloride begins in a few of the smaller grains in 30 seconds. About half 

 of the grains are affected and fully gelatinized in 33^ minutes, two-thirds are gelatinized in 7 minutes, 

 and all in 20 minutes. In many grains the reaction begins at projections on the margin. The reac- 

 tion is the same qualitatively as the grains of S. sibirica. 



With Purdy's solution there is a general reaction in 30 seconds. Most of the grains are com- 

 pletely gelatinized in 2 minutes, and all but rare resistant grains in 5 minutes. The reaction often 

 begins by a splitting off of the secondary additions to the grain, after which it proceeds as in the 

 grains of S. sibirica. 



STARCH OF SCILLA BIFOLIA. (Plate 35, figs. 209 and 210. Chart 143.) 



Histological Characteristics. — In form the grains are usually simple; there are a few double 

 and a very few compound grains. No pressure facets were noted. The surface of the grains is 

 rounded, but many are irregular. When on edge, some of them are seen to have a characteristic 

 ridge extending along the long axis of the grain, and probably around the entire circumference. 

 The surface of the grains, while rounded, is frequently somewhat irregular, owing to the unequal 



Curve of Reaction-Intensities of Starch of Scilla 

 peruviana. 



