130 



HISTOLOGIC PROPERTIES AND REACTIONS. 



reactions lower activity. The hybrid shows in the 

 reactions with polarization, gentian violet, and safranin 

 higher reactivities than either of the parents ; with iodine 

 intermediateness, but nearer to P. wallichii; and with 

 temperature practically the same reactivity as that of P. 

 wailichii. 



Table A 42 shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals 

 (minutes). 



Velocity-reaction Curves. 



This section treats of the velocity-reaction curves of 

 the starches of Phaius grandifolius, P. wallichiij and P. 

 hybridus, showing the quantitative differences in the be- 

 havior toward different reagents at definite time-inter- 

 vals. (Charts I) 574 to D 594.) 



Among the conspicuous features of these charts are: 

 The correspondence in the courses and the closeness of all 

 three curves in the several reactions. Owing to the very 

 rapid reactions of the starches with nitric acid, sulphuric 

 acid, hydrochloric acid, potassium hydroxide, potassium 

 sulphocyanate, potassium sulphide, sodium hydroxide, 

 sodium sulphide, strontium nitrate, and copper nitrate 

 (10 out of the 21 chemical reagents), satisfactory stud- 

 ies of the curves can not be made. Omitting these, the 

 curves tend to run very closely excepting in the react inns 

 with pyrogallic acid and copper nitrate, in each of which 

 there is well-marked separation. The curve of P. grandi- 

 folius is higher than that of the other parent in only 

 the chloral-hydrate reaction, and definitely lower in those 

 of the reactions with chromic acid, pyrogallic acid, po- 

 tassium iodide, sodium salicylate, calcium nitrate, ura- 

 nium nitrate, cobalt nitrate, cupric chloride, barium 

 chloride, and mercuric chloride. The curves of the hy- 

 brid vary in the different reactions in their parental 

 relationships. There is a marked tendency to inter- 

 mediateness, and there is about an equal tendency to 

 excess or deficit of reaction as there is to sameness to one 

 or the other and both parents, and there is about equal 

 inclination to one as to the other parent. In only two 

 of the charts (pyrogallic acid and cobalt nitrate) is there 

 evidence of an early period of resistance followed by a 

 moderate to rapid gelatinization. In both only two of the 

 starches (P. grandifolius aud P. hybridus) exhibit this 

 feature, but neither to a marked degree. The earliest 

 period of the experiments at which the curves are best 

 separated for differential purposes is with chromic 

 acid, potassium iodide, sodium salicylate, calcium nitrate, 

 uranium nitrate, cupric chloride, and mercuric chloride 

 at 5 minutes; pyrogallic acid and cobalt nitrate at 15 

 minutes; chloral hydrate at 45 minutes; and barium 

 chloride at 60 minutes. 



Eeaction-intensities of the Hybrid. 



This section treats of the reaction-intensities of the 



h\ lini] as regards sameness, intermediateness, excess, and 

 deficit in relation to the parents. (Table A 42 and 

 Charts D 574 to D 594.) 



The reactivities of the hybrid are the same as those 

 of the seed parent in the strontium-nitrate reaction; the 

 same as those of the pollen parent in the reactions with 

 temperature, sodium sulphide, and sodium salicylate; 

 the same as those of both parents with sulphuric acid, 

 hydrochloric acid, potassium hydroxide, potassium 

 sulphocyanate. and copper nitrate, in most all being too 

 fast for satisfactory differentiation ; intermediate with 

 iodine, chromic acid, pyrogallic acid, nitric acid, potas- 

 sium iodide, calcium nitrate, uranium nitrate, cobalt 

 nitrate, cupric chloride, barium chloride, and mercuric 

 chloride (in 4 being closer to the seed parent, in 2 closer 

 to the pollen parent, and in 4 being intermediate) ; 



