408 



DATA OF PROPERTIES OF STARCHES OF PARENT- AND HYBRID-STOCKS. 



from fine to moderately coarse and become broader at the 

 margin and usually intersect obliquely, but in some 

 grains the lines intersect either at the right angles or 

 are arranged in a median line with bisected ends. The 

 lines are more frequently straight, but occasionally bent 

 or bisected. Double figures are moderately numerous. 



The degree of polarization is high to very high (value 

 83) . The polarization in the different grains varies from 

 moderately high to very high, and considerable variation 

 may occur in the same aspect of a given grain. 



With selenife the quadrants are well defined, usually 

 unequal in size, and generally regular in shape. The 

 colors are generally pure. 



Iodine Reactions. 



With 0.25 per cent Lugol's solution the grains imme- 

 diately color a moderately light to moderate blue-violet 

 (value 45) ; the color deepens until it is moderately deep 

 to deep. With 0.125 per cent Lugol's solution the grains 

 color a light blue-violet, and the color deepens quickly to 

 moderately deep. After heating in water until the 

 grains are gelatinized and then adding a 2 per cent 

 Lugol's solution the grains color a light to deep blue, 

 usually with a reddish tint, the mean is moderate in 

 depth and the starch solution colors a deep indigo-blue. 

 If the preparation is boiled for 2 minutes and then treated 

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

 a light to deep blue usually tinged with red. The cap- 

 sules color a moderate old-rose to moderate amethyst, 

 the majority a moderate old-rose and the starch solution 

 colors a very deep indigo-blue. 



Aniline Reactions. 



With gentian violet the grains stain at once very 

 lightly ; and in half an hour they are moderately colored 

 (value 50). 



With safranin the grains stain very lightly, and in 

 half an hour they are moderate to moderately deep in 

 color (value 55). 



Temperature Reactions. 



The majority of the grains are gelatinized at 73° 

 to 74° C, and of all but rare grains at 75° to 76° C, 

 mean 75.5° C. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 about 5 per cent of the entire number of grains and 7 

 per cent of the total starch in 5 minutes; in about 20 

 per cent of the grains and 27 per cent of the total starch 

 in 15 minutes; in about 30 per cent of the grains and 37 

 per cent of the total starch in 30 minutes ; in about 39 per 

 cent of the grains and 42 per cent of the total starch 

 in 45 minutes; in about 43 per cent of the grains and 45 

 per cent of the total starch in 60 minutes. (Chart D 43.) 



One or more bubbles, more frequently the former, ap- 

 pear at the hilum; and a fissure is occasionally present 

 at the hilum which becomes enlarged and more refractive. 

 The lamella? do not become any more distinct but the 

 entire grain is more refractive and a slightly more re- 

 fractive border is formed around the main body of the 

 grain. A delicate fissure may proceed from or intersect 

 the hilum which deepens and may branch as the reaction 

 proceeds. The methods of gelatinization are varied. 



In the most rapidly gelatinized grains, the process may 

 spread quickly through the mesial region, the refractive 

 border, especially at the proximal end, being the more 

 resistant. Gelatinization may start at the distal margin 

 when the hilum is markedly eccentric ; or from both ends 

 in the long slender type with centric or nearly centric 

 hilum. A pitted appearance may appear in an area of the 

 marginal border directly underlying the capsule, followed 

 by gelatinization of this area ; the process may then spread 

 through the grain, the more resistant starch being located 

 in a narrow band at the proximal end and sides nearby. 

 The starch through the mesial region is often disorgan- 

 ized with the appearance of irregularly arranged refrac- 

 tive granules along the course of the longitudinal fissure ; 

 and the most resistant starch is divided into granules 

 linearly arranged following the formation of numerous 

 short fissures or strias in this area. The starch at one 

 side of the proximal end is generally less resistant than 

 that of the opposite side. 



The gelatinized grains are swollen and considerably 

 distorted, so that they do not resemble the form of the 

 untreated grain. 



The reaction with chromic acid begins in a few grains 

 in 1 minute. Complete gelatinization occurs in less 

 than 0.5 per cent of the entire number of grains and 1 

 per cent of the total starch in 5 minutes ; in about 1 per 

 cent of the grains and 25 per cent of the total starch in 

 15 minutes ; in about 55 per cent of the grains and 90 per 

 cent of the total starch in 20 minutes ; in about 85 per cent 

 of the grains and 96 per cent of the total starch in 25 

 minutes ; in more than 99 per cent of both the grains and 

 total starch in 30 minutes. (Chart D 44.) 



The reaction with pyrogallic acid begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 about 9 per cent of the entire number of grains and 10 

 per cent of the total starch in 5 minutes ; in about 40 per 

 cent of the grains and 67 per cent of the total starch in 

 15 minutes; in about 65 per cent of the grains and 80 

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

 75 per cent of the grains and 90 per cent of the total 

 starch in 45 minutes ; in about 86 per cent of the grains 

 and 95 per cent of the total starch in 60 minutes. (Chart 

 D45.) 



The reaction with nitric acid begins in a few grains in 

 half a minute. Complete gelatinization occurs in about 

 3 per cent of the entire number of grains and 4 per cent 

 of the total starch in 5 minutes; in about 15 per cent 

 of the grains and 17 per cent of the total starch in 15 

 minutes ; in about 25 per cent of the grains and 30 per 

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

 of the grains and 43 per cent of the total starch in 45 

 minutes ; in about the same percentage of grains and 56 

 per cent of the total starch in 60 minutes. (Chart D 46.) 



The hilum swells but no bubble was detected thereat. 

 If a fissure is found at the hilum it becomes enlarged 

 and more refractive, but loses its refractivity without 

 the appearance of a bubble. The entire grain becomes 

 refractive and the lamella? are not demonstrable with the 

 exception of one which moderately often forms a de- 

 marcation between the main body of the grain and a 

 border of slightly greater refractivity. Either one or 

 two fissures, according to the shape of the grain, may 

 proceed distally from the hilum, or when but one is 

 present it may intersect this point. The progress of 



