MUSA. 



733 



In the character and the arrangement of the lamella; 

 M. hybrida shows a very much closer relationship to 

 M. gilletii than to M. arnoldiana, hut in number the 

 reverse. 



In size the grains vary from the smaller which are 

 5 by 5/x, to the larger which are 60 by 34/*, in Length and 

 breadth. The common sizes are 34 by 22/i and :i I by 30/i. 

 In size the grains of M. hybrida are much closer bo those 

 of M. gilletii than of M. arnoldiana, but they may be 

 larger than the grains of either parent. 



Polariscopic Properties. 



The figure is as distinct and as well denned as in 

 M. gilletii. The lines, as in M. gilletii, sometimes cross 

 at right angles or at acute angles of varying degree. 

 They are not more often bent or bisected than in M. 

 gilletii. 



The degree of polarization varies from low to high 

 (value 50), more than in either parent, but nearer to 

 M. gilletii than to M. arnoldiana. There are more grains 

 with a high degree of polarization and there is less varia- 

 tion in a given aspect of an individual grain than in 

 either parent. 



With selenite the quadrants as in M. gilletii are often 

 clean-cut and are unequal in size, but not often irregular 

 in shape. The colors are somewhat more often pure than 

 in M. gilletii and much more often than in M. arnoldiana. 



In the character of the figure, the degree of polari- 

 zation, and the appearances with selenite M. hybrida 

 shows a closer relationship to M. gilletii than to M. 



arnoldiana. 



Iodine Reactions. 



With 0.25 per cent Lugol's solution the grains all 

 color a moderate blue-violet (value 50), the same as in 

 M. gilletii. With 0.125 per cent Lugol's solution the 

 grains all color lightly to moderately as in M. gilletii, 

 some more than others. After heating in water until 

 all the grains are gelatinied and then treating with a 2 

 per cent Lugol's solution, the gelatinized grains vary in 

 color from a light to moderate indigo ; and the solution 

 is a deep indigo as in M. gilletii. If the preparation is 

 boiled for 2 minutes and then treated with an excess 

 of a 2 per cent Lugol's solution, many of the grain- 

 residues color a light indigo, the capsules a red or a red- 

 dish violet, and the solution a very deep indigo as in 

 M. gilletii. Qualitatively and quantitatively the reac- 

 tions with iodine show a much closer relationship to M. 

 gilletii than to M. arnoldiana. 



Aniline Reactions. 



With gentian violet the grains all color very lightly 

 at once, and in 30 minutes they are lightly to deeply 

 colored (value 45), the same as in M. gilletii. 



With safranin the grains all color very lightly at once, 

 and in half an hour they are lightly to deeply colored 

 (value 50), the same as in M. gilletii. 



In the reaction with aniline stains, M. hybrida shows 



a much closer relationship to M. gilletii than to M. 



arnoldiana. 



Temperature Reactions. 



The temperature of gelatinization of the majority 

 of the grains is 65.2° .to 67° C, and of all 69° to 

 70.5° C, mean 69.75° C. The temperature of gela- 

 tinization of M. hybrida is higher than that of either 



parent, but is much closer to M. gilletii (mean 68.4°) 

 than to M. arnoldiana (mean 65°). 



Effects of Various Reagents. 



The reaction with chloral hydrate begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

 about 10 per cent of the entire number of grains and 

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

 51 per cent of the grains and 58 per cent of the total 

 starch in 15 minutes; in about 66 per cent of the grains 

 and 73 per cent of the total starch in 30 minutes; 

 in about 68 per cent of the grains and 70 per cent of tie' 

 total starch in 45 minutes; in about 73 per cent of the 

 grains and 77 per cent of the total starch in 60 minutes. 

 (Chart D553.) 



The hilum becomes distinct, attended by the forma- 

 tion of a bubble in a great majority of the grains. More 

 than in either parent. The hybrid in this characteristic 

 is closer to M. gilletii than to M. arnoldiana. The 

 lamellae, as in M. gilletii, are at first invisible, but later 

 become very distinct, especially just before gelatiniza- 

 tion. Gelatinization begins at. the distal margin and 

 progresses according to the two types described for both 

 parents. In the majority of the grains the process n 

 that seen in a majority of the grains of M. gille/ii and 

 in a small minority of the grains of M. arnoldiana. 

 The gelatinized grains arc as much swollen, have cap- 

 sules as thin, and are as much distorted, as in M. gilletii. 

 In this reaction M. hybrida shows qualitatively a some- 

 what closer relationship to M. gilletii than to M. 

 arnoldiana. 



The reaction with chromic acid begins in a few grains 

 in 15 seconds. Complete gelatinization occurs in about 16 

 per cent of the entire number of grains and 22 per cent 

 of the total starch in 5 minutes; in about 54 per cent 

 of the grains and 79 per cent of the total starch in 15 

 minutes; in about 88 per cent of the grains and 97 per 

 cent of the total starch in 30 minutes. (Chart D 554.) 



The hilum and lamellae are as distinct as in M. gil- 

 letii. Gelatinization begins at the hilum and progresses 

 according to the two methods described for both parents. 

 The method which is seen in the elongated grains, which 

 are also in a great majority, is in nearly all the same 

 as that noted in the elongated grains of M. gilletii, but 

 in some it is the same as that seen in the elongated grains 

 of M. arnoldiana. The method found in the few broad 

 forms is the same as in both parents. In this reaction 

 M. hybrida shows, qualitatively, a closer relationship 

 to M. gilletii than to M. arnoldiana. 



The reaction with pyrogallic acid begins in 1 minute. 

 Complete gelatinization occurs in about 5 per cent of the 

 entire number of grains and 14 per cent of the total 

 starch in 5 minutes ; in about 20 per cent of the grains 

 and 55 per cent of the total starch in 15 minutes; in 

 about 32 per cent of the grains and 73 per cent of the 

 total starch in 30 minutes ; slight progress in 45 minutes ; 

 in about 34 per cent of the grains and 79 per cent of the 

 total starch in 60 minutes. (Chart D 555.) 



The reaction is much less rapid than in M. arnoldiana 

 and much nearer that of M. gilletii; at first the reac- 

 tion is more rapid than in the latter species, but later 

 it is more retarded. There appears to be two types of 

 grains, one of which is much more easily gelatinized than 

 the other. 



