128 



HISTOLOGIC PROPERTIES AND REACTIONS. 



stances to be well separated from the curve of .1/. arnold 

 iana. The tendencj for the hybrid reactions throughout 

 pting those with nitric arid, sulphuric acid, and po- 

 tassium hydroxide which are so rapid that do satisfac- 

 tory differentiation can be made, and in that with pyro- 

 gallic acid, iii which the curve is practically identical 

 with that nl the pollen parent ), tu be lower than that in 

 either parent ; and also to show a distinctly closer rela- 

 tionship to M. gilletii than to M. arnoldiana. 



(3) The considerable differences in the interrelations 

 of the three curves: Thus, in the reactions with chloral 

 hydrate, chromic acid, sodium salicylate, calcium ni- 

 trate, uranium nitrate, strontium nitrate, and barium 

 chloride the curves are quite evenly separated, the 

 curve of .1/. gilletii in each chart being between the 

 of .1/. arnoldiana and the hybrid. In the reac- 

 tions with pyrogallic acid, nitric acid, potassium iodide, 

 potassium sulphocyanate, potassium sulphide, sodium 

 hydroxide, sodium sulphide, cobalt nitrate, copper ni- 

 trate, eupric chloride, and mercuric chloride there is 

 an obvious pairing of the curves of M. gilletii and the 

 hybrid, the curves being to more or less marked de- 

 -i pa rated from the curve of M. arnoldiana, and 

 from each other, excepting in the latter in the pyrogallic- 

 ai id reactions, where the curves of M. gillelii and the 

 hybrid are practically identical. In the reactions with 

 nitric acid, potassium iodide, and sodium hydroxide the 

 only important differences are noted at the very begin- 

 ning of gelatinization. In the other reactions, with the 

 exceptions noted, while the curves tend in general to run 

 closely, there are sufficient differences to permit of 

 diagnosis. 



i i i Aii early period of resistance is noted in very 

 the reactions. In fact, there is generally a marked 

 tendency for an immediate high to very high degree of 

 reactivity which may be followed by a progressively les- 

 sening. An early period of resistance is seen in the 

 reactions of chromic acid with .1/. hybrida, of pyrogallic 

 acid. and. particularly, of barium chloride, with both 

 M. gilh Hi and .1/. hybrida. 



(5) The earliest period during the 60 minutes of 

 observation at which the curves are best separated for 

 the differentiation of the three starches is variable with 

 the different reagents. Tn case of the very rapid reac- 

 tion^, including those with nitric acid, sulphuric acid, 

 hydrochloric acid, potassium hydroxide, potassium 

 e, potassium sulphocyanate, potassium sulphide, 

 ami sodium hydroxide, the period is noted within the 

 minute of the reactions; in those with chromic 

 acid, pyrogallic acid, sodium sulphide, sodium salicylate, 

 call turn nitrate, uranium nitrate, strontium nitrate, cal- 

 nitiate, copper nitrate, eupric chloride, and mer- 

 chloride within 5 minutes; and in those with 

 chloral hydrate and barium chloride within 15 minutes. 



From (hi-- data the besl period for the differentiation of 



members of this genus would be. perhaps, on the whole, 5 

 minutes after the beginning of the reaction; or better. 

 to use in most cases weaker reagents. 



Reaction-intensities of the Hybrid. 



This section treats of the reaction-intensities of the 

 hybrid as regards sameness, intermediateness, excess, and 



i in relation to the parents. (Table A 41 and 

 ( harts D 553 to D 573.) 



The reactivities of the hybrid are the same as those 



of the seed parent in no reaction; the same as those of 

 the pollen parent in the reactions with iodine, gentian 

 triolet, sal'ranin, and pyrogallic acid ; the Mime as t hose of 

 both parents in none: intermediate with hydrochloric 

 acid, ami potassium hydroxide, being closer t" the pollen 

 parent in one and mid-intermediate in the other; highest 

 in none; and the lowest with polarization, temperature, 

 chloral hydrate, chromic acid, nitric acid, sulphuric acid, 

 potassium iodide, potassium sulphocyanate, potassium 

 sulphide, sodium hydroxide, sodium sulphide, sodium 

 salicylate, calcium nitrate, uranium nitrate, strontium 

 nitrate, cobalt nitrate, copper nitrate, eupric chloride, 

 barium chloride, and mercuric chloride, in all of which 

 being closer to the pollen parent. 



The following is a summary of the reaetion-inb 

 ties: Same as seed parent, 0; same as pollen parent, 4; 

 same as both parents, 0; intermediate, 2; highest, 0; 

 lowest, 20. 



Lowest reactivity of the three starches and sameness 

 and inclination to the pollen parent are two features that 

 stand out with marked conspicuousness. The pollen 

 parent seems to have been pre-eminent in determining 

 the characters of the starch of the hybrid, inasmuch as in 

 25 of the 26 reactions this parent bears the closer rela- 

 tionship to the hybrid, while in the remaining reaction 

 there is mid-intermediateness, but of doubtful valuation. 



Composite Curves of the Reaction-intensities. 



This section treats of the composite curves of the 

 reaction-intensities, showing the differentiation of the 

 -tin', hes of Musa arnoldiana, 31 . gilletii, and 31. hybrida. 

 (Chart E 41.) 



The most conspicuous features of the chart are: The 

 general correspondence in the ups and downs of the 

 curves, excepting in the case of M. arnoldiana in many 

 reactions which occur so rapidly that differences are no! 

 satisfactorily demonstrated. The three curves from the 

 polarization to the sulphuric acid reactions are in close 

 accord, hut from the latter on to the sodium-sulphide 

 reaction the curve of M. arnoldiana shows practically 

 no change, and from then on such alterations as are 

 exhibited occur within the 5-minute Hunt, excepting in 

 the barium-chloride reaction, in wdiieh the limit is ex- 

 tended to 15 minutes. With .1/. gilletii and .V. hybfida, 

 however, the variations from reagenl to reagent are com- 

 monly well marked. With somewhat weaker reagents the 

 curve of ,1/. arnoldiana would in all probability corre- 

 spond in its variations with the curves of M. gilletii and 

 the hybrid. The curve of .1/. arnoldiana is the highest 

 throughout, excepting in the polarization reaction, and 

 in many instances it is much higher than the curve "f 

 31. gilletii and the hybrid. The curve of .1/. gilletii is 

 r than the curve of .1/. hybrida in the reaction with 

 temperature, chloral hydrate, hydrochloric acid, potas- 

 sium sulphocyanate, potassium sulphide, sodium hydrox- 

 ide, sodium salicylate, uranium nitrate, and strontium 

 nitrate : and the same or nearly the same in all other reac- 

 tions, excepting with polarization, in which it is lower, 

 the same, or nearly the same. The best reagents in the 

 differentiation of these two starches are chloral hydrate, 

 potassium sulphide, sodium hydroxide, sodium salicy] ite, 

 uranium nitrate, and strontium nitrate. The very high 

 reactions of 31. arnoldiana with chromic acid, pyrogallic 



