CYMBIDIUM. 



761 



gelatinized and then adding 2 per cent Lugol's solution, 

 most of the grains color a moderate blue with a reddish 

 tint, and the solution colors a moderate to deep indigo- 

 blue. If the preparation is boiled for 2 minutes and 

 then treated with an excess of 2 per cent Lugol's solu- 

 tion, the grain-residues become a deep blue with reddish 

 tint, and most of the capsules a light brick-red, and a 

 few wine-red ; the solution colors very deep blue. After 

 boiling there are very few grain-residues, but there are 

 many capsules. 



ANILINE REACTIONS. 



With gentian violet most of the grains immediately 

 color lightly, a few moderately. In 30 minutes they staiu 

 a moderate to moderately deep violet (value 55) with a 

 larger proportion of the former depth. 



With safranin the grains immediately color light to 

 moderate. In 30 minutes most of them appear moder- 

 ately stained, with a few moderately deep (value 52). 



TEMPERATURE REACTIONS. 



The majority of the grains are gelatinized at 58 

 to 60 C., and of all at 62 to 63 C., mean 62.5 C. The 

 very small isolated grains and the rare quite large isolated 

 grains are the most resistant. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins immediately. 

 Complete gelatinization occurs in about 85 per cent of 

 the entire number of grains and 90 per cent of the total 

 starch in 2 minutes; in about 93 per cent of the grains 

 and 95 per cent of the total starch in 3 minutes; in more 

 than 99 per cent of the grains and total starch in 5 

 minutes. (Chart D 616.) 



The hilum rapidly becomes very distinct, and a bubble 

 usually is formed there which remains enlarged until the 

 process of gelatinization has reached the hilum. The 

 lamella? slowly become distinct, especially in the more 

 resistant grains, but just before they are gelatinized they 

 become indistinct, as the starch comprising them becomes 

 finely granular. A refractive band is formed about the 

 margin of the more resistant grains and becomes very 

 broad, receding as gelatinization advances from the mar- 

 gin inward. Gelatinization always begins at the distal 

 end and, if there are pressure facets, at the sharp corners. 

 This is followed by gelatinization of the marginal starch 

 at the sides, or, rarely, at the proximal end. Gela- 

 tinization progresses much more rapidly over the surface 

 than the interior of the grain, and there is frequently 

 a resistant central core left when all the rest is gelatinous, 

 but this also becomes gelatinous in time. When the hilum 

 is reached the bubble, which is usually present, swells sud- 

 denly, and is sometimes separated into two or three bub- 

 bles, which then shrinks and disappears. The most re- 

 sistant starch is either in a central core as noted, or else 

 just distal or just proximal to the hilum. The gela- 

 tinized grains are large and somewhat distorted, but 

 retain some of the form of the untreated grain. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 90 per cent of the 

 entire number of grains and 98 per cent of the total starch 

 in 2 minutes; in over 99 per cent of both the grains and 

 total starch in 5 minutes. 



The hilum becomes distinct and the lamellae are dis- 

 tinct at first but later become obscured. Gelatinization 

 25 



begins at the hilum, which enlarges somewhat, and the 

 grain becomes divided by fine stria? radiating from the 

 hilum, while a few rather small granules are formed by 

 the extension of 2 or 3 fissures from the hilum into the 

 surrounding starch. The hilum then continues to en- 

 large and the grain to swell, and the more resistant starch 

 is pushed to the margin where it forms a smooth non- 

 striated, non-lamellated band. This band becomes nar- 

 rower and more and more nearly transparent until it 

 and the capsule are dissolved at one point and the semi- 

 fluid gelatinous mass in the interior flows out and is 

 dissolved while the capsule collapses and is finally also 

 dissolved, a few granules and shreds of capsular starch 

 persisting for some time after the rest has been dissolved. 



The reaction with pyror/aUic acid begins immediately. 

 Complete gelatinization occurs in about 87 per cent of the 

 entire number of grains and 98 per cent of the total starch 

 in 5 minutes; in about 98 per cent of the grains and 

 over 99 per cent of the total starch in 15 minutes. (Chart 

 DG17.) 



The reaction with nitric acid begins immediately; 

 nearly all the grains are gelatinized in 15 seconds; all in 

 30 seconds, but rare resistant grains which take from 2 

 to 3 minutes for the completion of the reaction. The 

 reaction is so rapid that all the details can not be satis- 

 factorily determined. The hilum swells, and rarely fis- 

 sures are observed passing from it; during the process 

 an invagination occurs at one or more points. The 

 gelatinized grains are much swollen and distorted so that 

 they do not resemble the form of the untreated grain. 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization (100 per cent) of all the grains 

 occurs in 15 seconds. 



The reaction with hydrochloric acid begins imme- 

 diately and gelatinization is practically instantaneous; 

 complete gelatinization of all grains occurs in 10 seconds 

 or earlier. The reaction is so rapid that the minute steps 

 of the process can not be studied. The gelatinized grains 

 are much swollen and considerably distorted, the latter 

 markedly so at the distal margin ; the capsule at the proxi- 

 mal end and sides is thicker and often quite refractive. 

 This capsule gradually becomes less distinct until it is 

 dissolved in all but rare grains in 30 minutes. 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization of all the grains occurs 

 in 10 seconds. Since gelatinization is complete when the 

 slide is placed under observation, the process may be 

 instantaneous. The reaction is so rapid that the details 

 can not be satisfactorily demonstrated. The gelatinized 

 grains are much swollen and considerably distorted at 

 the distal margin. 



The reaction with potassium iodide begins imme- 

 diately, all but a few resistant grains being gelatinized 

 in 15 seconds. The reaction is completed in 30 seconds, 

 with the exception of rare scattered separated grains, 

 which are gelatinized in 1 minute. The reaction is so 

 rapid that no details can be made out. The gelatinized 

 grains are swollen and considerably distorted, so that 

 they do not resemble the shape of the untreated grain. 



The reaction with potassium sulphocyanate begins im- 

 mediately ; nearly all the grains are gelatinized in 5 sec- 

 onds, all in 10 seconds. The reaction is so rapid, that 

 no details of the process can be determined. The gela- 



