GENUS SPARAXIS. 767 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains color immediately a fairly 

 deep blue-violet, which deepens rather rapidly; with 0.125 per cent solution they color a light 

 blue-violet, which deepens rather rapidly. After heating in water until the grains are gelatinized 

 and then treating with iodine, the solution colors a greenish-blue, most of the grains a deep 

 purplish-blue, and the rare, large, ellipsoidal grains a deep reddish-violet. When the solution is 

 boiled for 2 minutes and then treated with iodine, the solution becomes a deep indigo-blue and the 

 grain-residues a light blue. With an excess of iodine the solution becomes a greenish-blue and the 

 grain-residues a deep reddish-purple, while the capsules are colored a deep heliotrope to a wine red. 



Staining Reactions. With gentian violet the grains begin to stain at once and in 30 minutes 

 are lightly stained. 



With safranin the grains begin to stain at once and in 30 minutes are lightly colored. Even 

 the rare ellipsoidal and pyriform grains stain lightly, although a little deeper than the others. 



Temperature Reaction. The temperature of gelatinization is 71 to 72 C, mean 71.5. 



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

 few are gelatinized in 30 seconds, nearly all in a minute, and all but a few resistant grains in 2 min- 

 utes. The reaction is complete in the latter in 8 minutes. The entire grain is colored an old-rose. 

 Either a dark spot, a ring, or an irregular looped structure usually appears at the hilum. Gelatin- 

 ization begins at the edges of the pressure facets, which are indicated by a dark blue rim on the dome- 

 shaped grains; this process spreads around the margin of the grain and then towards the center, 

 until the entire grain is gelatinized. In round grains gelatinization begins uniformly on all parts 

 of the surface and proceeds towards the center. Both the dark ring and the looped structure grad- 

 ually become much enlarged during gelatinization, but finally collapse, and clouds of the dark- 

 blue color then flow over the entire grain and the reaction is complete. The grains with regular 

 outline and those in which the structures at the hilum swell considerably are most resistant to the 

 reagent. The gelatinized grains are swollen, but retain the general shape of the untreated grain. 



The reaction begins immediately with chromic acid. A few are dissolved in 30 seconds, nearly 

 all in a minute, and all but rare resistant grains in 2 minutes. The reaction is complete in these in 

 5J/^ minutes. The hilum swells and thick fissures radiate from it towards the corners of the dome- 

 shaped and somewhat quadrangular grains; the lamellae become fairly distinct and are striated, 

 and all but the thick, slowly reacting capsule is quickly gelatinized. The capsule is quite resistant, 

 but as the grain swells it is finally ruptured, usually at the facets when present, and the entire grain 

 passes into solution. In the round grains the process is the same, excepting that the rather thick, 

 radiating fissures are not formed. 



The reaction begins immediately with pyrogallic add. A few grains are gelatinized in 15 seconds 

 and all but a few resistant grains in 30 seconds. The reaction is complete in the latter in 60 seconds. 

 The hilum swells and fissures proceed from it towards the corners of the faceted grains. In the 

 round forms the process is similar, but the reaction is usually slower and the lamellae can often be 

 more clearly distinguished. The gelatinized grains retain the general shape of the untreated grain, 

 but are much swollen and somewhat distorted at the facets. They are bounded by a fairly thick 

 outer layer in which the remains of 2 lamellae may sometimes be distinguished. 



The reaction begins inamediately with ferric chloride. A few grains are gelatinized in 30 seconds, 

 nearly all in 13^ minutes, and all but a few resistant grains in 4 minutes. The reaction is complete 

 in the latter in 12 minutes. The hilum swells and a bubble often forms there. A border which is 

 more transparent forms around the grain. Later the lamellae in this area become more clearly 

 defined. Gelatinization usually begins at the facets, followed by a rapid distension of the capsule 

 at these points. This process sometimes spreads around the whole surface of the grain, the central 

 portion being the last to undergo gelatinization. In some grains the hilum swells and gelatiniza- 

 tion begins in the center and advances gradually towards the surface. This form of gelatinization 

 is found chiefly in the round grains. The gelatinized grains are much swollen and somewhat dis- 

 torted at the facets, but retain the general shape of the untreated grain. 



With Purdy's solution the reaction begins immediately. A few are gelatinized in 30 seconds, 

 nearly all in a minute, and all but rare resistant grains in 2 minutes; many of the latter are not 

 affected beyond the first steps of the reaction, even in 30 minutes. The hilum swells and two or 

 more radiating fissures proceed from it towards the corners of the grain, and the lamella become more 

 distinct and are striated. Gelatinization follows the course of the fissures until all the starch be- 

 comes soluble except 2 or 3 of the outermost lamellae and the capsule. In the round grains the hilum 



