MUSA. 



727 



end and sides nearby ; as the hilum enlarges it pushes this 

 band outward at the proximal end, and the band grows 

 narrower and more nearly .transparent at this point; 

 meanwhile the portion of the grain distal to the 2 fur- 

 rows becomes divided by regular, radiating fissures. The 

 lamella become very distinct and more refractive. This 

 portion of the grain now begins to gelatinize, and as the 

 grain swells it loses its lamellated appearance and be- 

 comes more refractive and more hyaline in appearance, 

 then it is divided into 3 or 4 pyramidal masses by wedge- 

 shaped fissures which gelatinize with moderate rapidity 

 from their apices toward their bases. Finally, this distal 

 starch forms a broad, very nearly transparent, granular 

 mass at the distal margin. Meanwhile the thick, homo- 

 geneous, refractive band at the proximal end and sides 

 has been growing thinner and more hyaline, especially 

 at the proximal end. It is finally gelatinized before the 

 granular mass at the distal end, which slowly gelatinizes 

 accompanied by considerable distortion of the capsule 

 of the distal end. The second method is observed in 

 the elongated grains. The hilum begins to swell and 2 

 fissures are seen to extend obliquely from either side of 

 the hilum toward the distal margin. The proximal 

 starch and that outside of the 2 fissures forms at the mar- 

 gin a thick, very refractive, homogeneous-looking band, 

 which is pushed outward and becomes very thin at the 

 proximal end as the hilum swells. In the starch com- 

 prehended between the 2 fissures, the lamellae become at 

 first very distinct, then fade as the starch becomes more 

 hyaline in appearance; next this starch is divided by 2 

 rows of fissures which slant upward from the sides and 

 meet in the line of the longitudinal axis of the grain. 

 The fissures increase in size as the grain continues to swell 

 and separate off successive filaments of starch, the inner 

 ends of which are free but the outer ends attached along 

 the line of the 2 original fissures. This process continues 

 until the distal end is nearly reached, and there the 

 starch, instead of being fissured, forms a broad, rather 

 granular mass at the margin. The filaments which have 

 been separated are meanwhile rapidly gelatinized. The 

 marginal starch at the proximal end and side rather 

 slowly gelatinizes and finally the granular mass at the 

 distal end, with some distortion of the capsule at the 

 latter point. The gelatinized grains are very much 

 swollen, have rather thick capsules, and are considerably 

 distorted, especially at the distal end, but retain some 

 resemblance to the form of the untreated grain. 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 97 per cent of 

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

 starch in 15 seconds; in about 98 per cent of the grains 

 and 99 per cent of the total starch in 30 seconds. (Chart 

 D556.) 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 90 per cent of 

 the entire number of grains and 95 per cent of the total 

 starch in 30 seconds ; in about 99 per cent of the grains 

 and in more than 99 per cent of the total starch in 45 

 seconds. ( Chart D 557.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 94 per 

 cent of the entire number of grains and 99 per cent of 

 the total starch in 30 seconds. (Chart D 558.) 



The reaction with potassium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 97 per 

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

 the total starch in 15 seconds ; in more than 99 per cent 

 of the grains and total starch in 30 seconds. (Chart 

 D 559.) 



The reaction with potassium iodide begins imme- 

 diately. Complete gelatinization occurs in about 85 per 

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

 the total starch in 1 minute ; in about 98 per cent of the 

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

 in 3 minutes; in 99 per cent of the grains and in more 

 than 99 per cent of the total starch in 5 minutes. (Chart 

 D560.) 



The reaction with potassium sulphocyanate begins 

 immediately. Complete gelatinization occurs in about 

 80 per cent of the entire number of grains and 96 per 

 cent of the total starch in 30 seconds; in about 98 per 

 cent of the grains and in more than 99 per cent of the 

 total starch in 1 minute. (Chart D 561.) 



The reaction with potassium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 97 per 

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

 total starch in 15 seconds; in more than 99 per cent of 

 the grains and total starch in 30 seconds. (Chart D 562.) 



The reaction with sodium hydroxide begins imme- 

 diately. Complete gelatinization occurs in about 98 per 

 cent of the entire number of grains and 99 per cent of 

 the total starch in 30 seconds; in more than 99 per cent 

 of the grains and total starch in 1 minute. (Chart 

 D563.) 



The reaction with sodium sulphide begins imme- 

 diately. Complete gelatinization occurs in about 80 per 

 cent of the entire number of grains and 96 per cent of 

 the total starch in 30 seconds ; in about 96 per cent of the 

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

 in 1 minute. (Chart D 564.) 



The reaction with sodium salicylate begins imme- 

 diately. Complete gelatinization occurs in about 66 per 

 cent of the entire number of grains and 75 per cent of 

 . the total starch in 3 minutes ; in about 80 per cent of the 

 grains and 95 per cent of the total starch in 5 minutes ; 

 in about 99 per cent of the grains and in more than 99 

 per cent of the total starch in 10 minutes. (Chart 

 D565.) 



The hilum becomes distinct, attended by the forma- 

 tion of a bubble in very few grains. The lamella? are 

 at first invisible but gradually become distinct in most 

 of the grains. The grains become more refractive; the 

 first part of the grain to show this is a band of starch 

 at the margin which is broader at the distal end than else- 

 where. Gelatinization begins at the distal margin and 

 progresses according to but one method. Gelatinization 

 advances toward the hilum, preceded by an indistinctly 

 granular or pitted appearance of the surface of the grain. 

 The central portion of the grain is apparently the less 

 resistant to the reagent, as a broad refractive canal is 

 seen to extend through the center to the hilum, and the 

 bubble if present swells, shrinks, and disappears before 

 there is any indication on the surface of the grain that 

 the hilum is reached. Shortly the starch in the central 

 portion swells, splitting the ungelatinized material into 

 two pieces which are widely separated and gelatinize inde- 

 pendently of one another. In some grains gelatinization 



