GENUS ANTHOLYZA. 741 



Polariscopic Properties. The figtire is usually eccentric, distinct, and generally clear-cut. At 

 times its lines are less clearly defined in some portions of their length and tend to become broader 

 peripherally, especially close to the margin; they are sometimes curved or otherwise distorted. 

 Two or more figures may be seen on the surfaces of the facets and in the case of aggregates. 



The degree of polarization is fairly high, varying somewhat in different grains, but not very 

 much in different aspects of the same grain. In the same aspect of a grain it is sometimes lower 

 at the facets than in any other part. 



With selenite the quadrants are, as a rule, well defined, irregular in shape, and unequal in size. 

 The colors are usually pure. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains color a light blue-violet; 

 with 0.125 per cent solution they do not color perceptibly until after about 1 to 13^ minutes, then 

 very lightly, and the color deepens gradually. After heating in water until the grains are completely 

 gelatinized, the solution colors deeply and the swollen grains very deeply on the addition of iodine. 

 After boiling for 2 minutes the solution colors very deeply and the grain-residues fairly deeply. 

 In some of the grains, when an excess of iodine is added, violet-colored capsules can be seen. 



Staining Reactions. With gentian violet and with safranin the grains begin to stain at once 

 and in 30 minutes they stain fairly, a few more than others. 



Temperature Reaction. The temperature of gelatinization is 73 to 75 C, mean 74. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins in many grains in 

 30 seconds. All of the small and most of the medium-sized grains, constituting two-thirds of the 

 total number, are gelatinized in 5 minutes, four-fifths are affected in 10 minutes, gelatinization incom- 

 plete in an hour. The whole grain is colored deep violet; swelling begins at the distal end; then the 

 corners and edges of the facets grow very dark as they swell, and this process proceeds up along the 

 sides and inward, but not so rapidly as along the margin. The hilum is finally reached and swells, and 

 then the starch at the proximal end is gelatinized. The gelatinized grains are fairly large and retain 

 much of the original form of the grains, with usually a round, light space in the interior surrounded 

 by a rim of dark material. Some of the grains do not react at all or not fully, as they are observed 

 usually to have a fissure or cavity at the hilum. 



Reaction with chromic acid begins in most grains in 15 seconds and in all in 30 seconds, and is 

 over in 3 minutes. The hilum begins to enlarge and fine striae appear which radiate in all directions 

 from the hilum. The grain swells, and the central part becomes clear and is probably occupied 

 by a gelatinous semifluid mass. The more resistant starch is seen at the margin, where it forms at 

 first a thick, striated ring which shows two or three alternate refractive and non-refractive bands. 

 This ring grows progressively thinner as the grains continue to swell until it is very thin and trans- 

 parent. It is then dissolved at one point, either at the corner of facets or near the proximal end. 

 The gelatinized starch flows out and is dissolved, and the outer, thin capsule dissolves later. 



The reaction with pyrogallic acid begins in all the grains in 30 seconds. The hilum enlarges, lines 

 or fissures extend from it to the corners of the facets, and fine striae appear radiating in all directions 

 throughout the grain. The inner part now becomes filled with a semiliquid mass of starch and the 

 more resistant starch at the margin forms into a thick ring as the grain swells. This ring is striated 

 and marked by two or three alternate refractive and non-refractive bands. As the grain continues to 

 enlarge, the ring becomes somewhat thinner and quite transparent, but never grows very thin. The 

 swollen grains are large and somewhat distorted and folded, but retain much of their original forms. 



The reaction with ferric chloride begins in some grains in 2 minutes; about one-third, including 

 most of the small ones, are completely gelatinized in 15 minutes, and all in 40 minutes. The reaction 

 begins with the increase in size of the hilum. Lines or fissures extend from the hilum to the corners 

 of the facets, and these increase in size as the hilum swells. The grain swells and the interior be- 

 comes filled with a semiliquid mass. The process of gelatinization often takes place much naore 

 rapidly in one direction than in others, so that the grain at first swells more in this one direction. 

 Later, the same process takes place universally. The more resistant starch forms a very thick, 

 faintly striated band at the periphery. This slowly grows thinner and clearer until it is very thin 

 and transparent. The swollen grains are large and somewhat distorted. 



With Purdy's solution there is in 4 minutes a slight reaction in a few grains, which consists of 

 httle enlargement of the grain, the gelatinization of a small amount of starch which causes the hilum 

 to appear larger, and the appearance of fine striae which radiate from the hilum. There was no 

 further change of importance. 



