IRIS. 



653 



The lamella are somewhat more distinct and some- 

 what coarser than in I. iberica and have the same general 

 arrangement as in those grains, hut are usually not so 

 irregular. The number counted on the larger grains 

 varies from 10 to 20, usually 12, the same as in 7. iberica, 

 but less than in I. cengialli. In the character of the 

 lamelte I. dorak shows a somewhat closer relationship to 

 I. cengialli than to I. iberica, but there are very few 

 differences to be noted in the grains of the three starches. 



In size the grains vary from the smaller which are 

 4 by 4^t, to the larger which are 36 by 16/u, in length and 

 breadsh. The common sizes are 20 by 11/t and 16 by 

 12/x. The grains are somewhat closer in size to I. iberica 

 than to I. cengialli, but are, as a rule, somewhat smaller 

 than in either parent. 



Polariscopic Properties. 



The figure is as distinct and as well denned as in J. 

 iberica; somewhat less than in I. cengialli. The lines as 

 in. /. iberica usually cross at an acute angle which does 

 not vary greatly in the different grains. They are some- 

 what more often bent and bisected than in I. iberica, 

 and are very much more often bent than in I. cengialli. 



The degree of polarization varies from low to high 

 (value 50), the same as in I. iberica and 10 units lower 

 than in I. cengialli. There is the same amount of varia- 

 tion in a given aspect of the individual grains as in 7. 

 iberica. 



With selcnite the quadrants are usually as clear-cut 

 as in I. iberica, and less than in I. cengialti. They are 

 unequal in size and as irregular in shape as in I. iberica. 

 The colors are usually not pure as in that starch. 



In the character of the figure, the degree of polariza- 

 tion, and the appearances with selenite I. dorak shows 

 a closer relationship to I. iberica than to I. cengialli. 



Iodine Reactions. 

 With 0.25 per cent Lugol's solution the grains all 

 color a light to moderate violet tinged with blue (value 

 40), the same as in I. iberica and 5 units less than in 

 I. cengialti. With 0.125 per cent Lugol's solution the 

 grains all color a light violet, the same as in I. iberica 

 and lighter than in I. cengialti. 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 are deeply or moderately deeply colored as in 

 7. iberica and more than in I. cengialti; the solution 

 deeply colored as in I. iberica and less than in 7. cengialti. 

 If the preparation is boiled for 2 minutes and then 

 treated with an excess of a 2 per cent Lugol's solution, 

 most of the grain-residues are not colored, a few are 

 colored a very light indigo as in 7. iberica; the capsules 

 are all colored a deep wine-red as in 7. iberica; and the 

 solution a very deep indigo as in 7. iberica. Qualita- 

 tively and quantitatively the reactions with iodine show 

 a closer relationship to 7. iberica than to 7. cengialti. 



Aniline Reactions. 

 With gentian violet the grains, as in the parents, stain 

 very lightly at once, and in 30 minutes they are moder- 

 ately stained (value 50), 5 units more than in 7. cen- 

 gialti and 10 units more than in 7. iberica. There is a 

 greater proportion of grains which are moderately to 

 deeply stained than in 7. cengialti. 



With saf ranin the grains, as in the parents, stain very 

 lightly at once, and in 30 minutes they are moderately 

 stained (value 50), the same as in I. cengialli, and 5 

 units more than in I. iberica. 



In the reaction with aniline stains /. dorak Bhowe 

 a closer relationship to 7. cengialli than to 7. iberica. 



Temperature Reactions. 

 The temperature of gelatinization of the majority of 



the grains is 68° to 70° C, and of all is T0° to 72° C, 

 mean 71° C. The temperature of gelatinization of 7. 

 dorak is 0.8° C. less than that of 7. iberica and 4° 0. less 

 than that of 7. cengialli. It is therefore closer to 7. 

 iberica than to 7. cengialti. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins in 1 minute. 

 Complete gelatinization occurs in about 2 per cent of the 

 entire number of grains and 6 per cent of the total starch 

 in 5 minutes; in about 11 per cent of the grains and 17 

 per cent of the total starch in 15 minutes; in about 24 

 per cent of the grains and 33 per cent of the total starch 

 in 30 minutes; in about 38 per cent of the grains and 44 

 per cent of the total starch in 45 minutes ; in about 44 per 

 cent of the grains and 50 per cent of the total starch in 

 60 minutes. (Chart D 400.) 



The hilum, as in the parents, becomes distinct, at- 

 tended by the formation of a bubble in the majority of 

 the grains. The lamella, as in the parents, are not very 

 distinct and soon become obliterated as the reaction 

 progresses. The grain becomes more refractive after the 

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

 increased refractivity is the margin, around which, as in 

 7. iberica, a rather broad, not very refractive band is 

 formed. Gelatinization, as in the parents, begins at the 

 corners of the distal margin, and is preceded by the 

 appearance, as in 7. iberica, of cracks or fissures, which 

 separate the marginal material from the rest at these 

 points. Gelatinization progresses as in 7. iberica, except 

 that the longitudinal fissures noted in those grains are 

 more extensive, and more and larger granules are formed 

 and separated oft'. There are also more grains than in 

 7. iberica in which the proximal end begins to gelatinize 

 after gelatinization has progressed about halfway from 

 the distal end to the hilum. The process differs mark- 

 edly from that in 7. cengialti in which none of these 

 phenomena is noted. The gelatinized grains are much 

 swollen, have as thin capsules, and are as distorted as in 

 7. iberica. In this reaction 7. dorak shows qualitatively, 

 a closer relationship to 7. iberica than to 7. cengialti. 



The reaction with chromic acid begins in 30 seconds. 

 Complete gelatinization occurs in about 6 per cent of the 

 entire number of grains and 29 per cent of the total 

 starch in 5 minutes; in about 33 per cent of the grains 

 and 86 per cent of the total starch in 15 minutes; in 

 about 36 per cent of the grains and 95 per cent of the 

 total starch in 30 minutes; in about 46 per cent of the 

 grains and 97 per cent of the total starch in 45 minutes ; 

 in about 68 per cent of the grains and 98 per cent of the 

 total starch in 60 minutes. (Chart D401.) 



The reaction with pyrogallic acid begins in 30 sec- 

 onds. Complete gelatinization occurs in about 4 per cent 

 of the entire number of grains and 20 per cent of the 

 total starch in 5 minutes; in about 21 per cent of the 



