TRITONIA. 



687 



per cent of the total starch in 45 minutes; in about 28 

 per cent of the grains and 39 per cent of the total starch 

 in 60 minutes. (Chart D 490.) 



The reaction with potassium iodide begins imme- 

 diately. Complete gelatinization occurs in about 2 per 

 cent of the entire number of grains and 15 per cent of 

 the total starch in 5 minutes; in about 12 per cent of 

 the grains and 29 per cent of the total starch in !<"> 

 minutes; in about 10 per cent of the grains and 45 per 

 cent of the total starch in 30 minutes; in abnut 42 per 

 cent of the grains and G2 per cent of the total starch in 

 45 minutes; in about 50 per cent of the grains and 67 

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

 D491.) 



The hilum becomes moderately distinct, and the 

 lamella? are not visible. Gelatiuization begins at the 

 hilum, and after the initial enlargement, fine stria? 

 appear, radiating from the hilum to the margin. The 

 hilum and the grain continue to swell, and the more 

 resistant material is gathered at the margin in a striated 

 band, which, however, rapidly becomes thinner and more 

 nearly transparent. In some grains gelatinization be- 

 gins simultaneously at the hilum and at a point on the 

 margin, and a segment of the grain from the hilum to 

 the margin is rapidly gelatinized and the rest less rapidly. 

 The process is the same as already described. The gela- 

 tinized grains are large and somewhat distorted but 

 retain some of the form of the untreated grain. 



The reaction with potassium sulphocyanate begins 

 immediately. Complete gelatinization occurs in about 50 

 per cent of the entire number of grains and 78 per cent 

 of the total starch in 5 minutes ; in about 60 per cent 

 of the grains and 85 per cent of the total starch in 15 

 minutes ; in about 75 per cent of the grains and 93 per 

 cent of the total starch in 30 minutes; in about 80 per 

 cent of the grains and 95 per cent of the total starch in 

 45 minutes ; in about the same percentage of grains and 

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

 D492.) 



The reaction with potassium sulphide begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 1 per cent of the entire number of grains and 5 

 per cent of the total starch in 5 minutes ; in about 2 per 

 cent of the grains and 7 per cent of the total starch in 

 15 minutes ; slight advance in 30 minutes ; in about 3 

 per cent of the grains and 8 per cent of the total starch 

 in 45 minutes ; little if any further advance in 60 min- 

 utes. ( Chart D 493.) 



The reaction with sodium hydroxide 'begins imme- 

 diately. Complete gelatinization occurs in about 29 per 

 cent of the entire number of grains and 62 per cent of 

 the total starch in 5 minutes ; in about 44 per cent of the 

 grains and 77 per cent of the total starch in 15 minutes ; 

 in about 55 per cent of the grains and 81 per cent of the 

 total starch in 30 minutes; in about 59 per cent of tin- 

 grains and 84 per cent of the total starch in 45 minutes ; 

 in about 67 per cent of the grains and 87 per cent of the 

 total starch in 60 minutes. (Chart D494.) 



The hilum becomes very distinct and, if a pressure 

 facet is present, two fissures or canals may be seen to 

 extend from the hilum to the distal corners of the pres- 

 sure facet. The lamellae are not visible, probably due to 

 the masses of foreign matter which cling to the grains 

 in this preparation. Gelatinization, which is often pre- 



ceded by a pitted appearance, begins either at the hilum 

 alone, or at the hilum and one point on the margin simul- 

 taneously. The starch between these two points is rap- 

 idly gelatinized, and the remaining portion becomes 

 divided into fine spicules by stria? radiating from the 

 hilum, the starch nearest the hilum is now broken up 

 into rather fine granules which separate one from another 

 and gelatinize, finally there remains a very much swollen 

 grain, one segment of which is completely gelatinized, 

 and the rest has at the margin a thick, finely striated 

 band, inside of which is a number of granules. This band 

 becomes gradually thinner and more transparent until 

 complete gelatinization of the whole grain has occurred ; 

 some granules, however, persist for a long time in the 

 interior of the grain. The gelatinized grains are moder- 

 ately large and somewhat distorted, but show much of 

 the form of the untreated grain. 



The reaction with sodium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 14 per 

 cent of the entire number of grains and 25 per cent of 

 the total starch in 5 minutes ; in about 25 per cent of 

 the grains and 34 per cent of the total starch in 15 

 minutes; in about 31 per cent of the grains and 54 per 

 cent of the total starch in 30 minutes; in about 41 per 

 cent of the grains and 62 per cent of the total starch in 

 45 minutes; in about 59 per cent of the grains and 68 

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

 D495.) 



The reaction with sodium saUn/lnlc. begins imme- 

 diately. Complete gelatinization occurs in about 56 per 

 cent of the entire number of grains and 65 per cent of 

 the total starch in 5 minutes ; in about cS8 per cent of the 

 grains and 92 per cent of the total starch in 15 minutes; 

 in about 98 per cent of the grains and over 99 per cent 

 of the total starch in 30 minutes. (Chart D 496.) 



The hilum becomes distinct, and a bubble is often 

 formed there. The lamella? are not visible. Gelatiniza- 

 tion is preceded by a pitted appearance of the starch 

 at the distal end or, if the hilum is centric, of the 

 portion all around the margin. After the marginal 

 starch has gelatinized at various points, the remaining 

 inner part becomes invaded by small cracks into which 

 the reagent evidently penetrates, gelatinization of the 

 starch between these cracks ensuing in each case. When 

 the hilum is reached, it enlarges suddenly, and the bub- 

 ble, if present, swells, shrinks, and finally disappears. 

 The proximal starch is gelatinized, and finally a small 

 portion just distal to the hilum. The gelatinized grains 

 are moderately large and somewhat distorted, but retain 

 some of their original form. After one hour about 0.2 

 per cent of the grains are not gelatinized. 



The reaction with calcium nitrate begins imme- 

 diately. Complete gelatinization occurs in about 5 per 

 cent of the entire number of grains and 15 per cent of 

 the total starch in 5 minutes; in about 10 per cent of the 

 grains and 19 per cent of the total starch in 15 minutes ; 

 in about 12 per cent of the grains and 22 per cent of the 

 total starch in 30 minutes; in about 20 per cent of the 

 entire number of grains and 26 per cent of the total starch 

 in 45 minutes; in about 28 per cent of the grains and 

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

 D497.) 



The reaction with uranium nitrate begins imme- 

 diately. Complete gelatinization occurs in about 3 per 



