GENUS COCHLEAEIA. 873 



pletely gelatinized, the solution is well colored and the grains very deeply and uniformly upon the 

 addition of iodine. The grains are much swollen and distorted. After boiling for 2 minutes the 

 solution is colored very deeply, but the grain-residues lightly. When a slight excess of iodine is 

 added all of the capsules take a deep violet color and many of them contain blue-reacting starch. 



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

 after 30 minutes are fairly but not deeply stained. 



Temperature Reaction. — The temperature of gelatinization is 62° to 63° C, mean 62.5°. 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins immediately and is 

 over in 2 minutes. The hilum becomes distinct and the distal end darkens first, except in the elon- 

 gated grains with the hilum extending almost the whole length; in these the two ends darken, with- 

 out much swelling. This process spreads inward evenly over the whole grain. When the grain is 

 fully swollen there is commonly some irregular lobulation along the margin. The gelatinized grains 

 have a dark band around the margin and a lighter inner space. They retain much of the original 

 shape of the grain. 



Reaction with chromic acid begins immediately and is over in a minute. The hilum becomes 

 very prominent and swells. The starch at the margin of the grain forms a thick homogeneoas band 

 which, as the grain continues to swell, becomes progressively thinner until one side or one end be- 

 comes invaginated. The margin at one end of the grain dissolves, followed by rapid solution of 

 other parts of the capsule and of the entire contents. 



Reaction with pyrogallic add begins in 15 seconds and is over in IJ^ minutes. The hilum is 

 very prominent. The grain often begins to gelatinize at one end and, if the hilum is elongated, it 

 swells near the point at which reaction has begun. This is followed by progressive swelling, ap- 

 parently in segments, of the rest of the grain, with the formation of a clear inner space and a homo- 

 geneous marginal band. The direction of swelling is mainly longitudinal, very slightly transversely. 

 The grains are very much elongated and thin-walled, with small dents on the margin to mark the 

 different segments. In some grains the reaction may begin at both poles, and in such cases the 

 central part often does not show much swelling. In the round or nearly round grains the process 

 begins at the part most distant from the hilum, and from here it extends over the grain. When 

 the reaction is completed the grains are much lobulated and distorted. 



With ferric chloride the reaction begins in 15 seconds and is over in 2 minutes. The hilum is 

 prominent. The long grains show gelatinization, sometimes at one end, but often at both. The 

 starch at these points swells out to a marked degree. The middle portion of the hilum swells out 

 rapidly and divides the remaining portion of the grain into two parts, which gelatinize separately. 

 In the round and ovoid grains the process begins at the distal end, then at the other end, and finally 

 at the portion around the hilum, which often seems to have been separated from the rest by a cir- 

 cular fissure and to have gelatinized separately. As the grains swell and become large, they usually 

 invaginate at the distal end and sometimes have a segmented appearance. They are very large, 

 lobulated, and crumpled. 



The reaction with Purdy's solution begins in 10 seconds and is over in 5 minutes. The hilum 

 becomes very prominent and then swells. The swelling of the grain takes place to a greater extent 

 in the longitudinal than in the transverse axis. As the grain swells and the marginal band becomes 

 thinner and clear, invagination takes place usually at one end. The swollen grains are large, much 

 elongated, somewhat segmented, crumpled, and uneven. 



