112 



HISTOLOGIC PROPERTIES AND REACTIONS. 



in that with barium chloride. In all other instances 

 the most marked differentiation is noted early in the 

 reactions, with an inclination for the differences to 

 become less during the progress of the reactions. In 

 many instances the curves are so close as not to permit 

 of satisfactory differentiation, unless it be within the 

 first 5 minutes, as in the reactions with chromic acid, 

 pyrogallic acid, nitric acid, sulphuric acid, hydrochloric 

 acid, potassium hydroxide, potassium iodide, sodium sul- 

 phide, calcium nitrate, strontium nitrate, copper nitrate, 

 cupric chloride, and mercuric chloride; in others there 

 may be as good or better differentiation at a later period, 

 as in the reactions with chloral hydrate, potassium sul- 

 phide, sodium salicylate, uranium nitrate, cobalt nitrate, 

 and barium chloride. Gelatinization occurs with such 

 speed in the reactions with potassium sulphocyanate and 

 sodium hydroxide as to render satisfactory differentiation 

 impossible. 



(2) The higher reactivity of 7. persica var. purpurea 

 than of the other parent in the reactions with chloral 

 hydrate, sodium salicylate, and calcium nitrate ; the lower 

 reactivity with chromic acid, nitric acid, sulphuric acid, 

 potassium sulphide, sodium sulphide, uranium nitrate, 

 calcium nitrate, strontium nitrate, cobalt nitrate, cupric 

 chloride, barium chloride, and mercuric chloride; and 

 the same or practically the same reactivity with pyrogallic 

 acid, hydrochloric acid, potassium hydroxide, potassium 

 iodide, potassium sulphocyanate, sodium hydroxide, and 

 cupric chloride. In some of the reactions where the 

 curve is higher or lower the differences are unimportant 

 and probably fall within the limits of error of experiment. 



(3) The variable position of the hybrid curve in rela- 

 tion to one or both parental curves. There is a distinct 

 tendency to intermediateness, and one also equally strong 

 for the curve of the hybrid to be above or below the 

 parental curves. 



(4) There is an entire absence of any marked ten- 

 dency to a period of early resistance followed by rapid 

 reaction. There are mere suggestions of such resistance 

 as, for instance, in I. persica var. purpurea and the hybrid 

 in the chromic-acid and uranium-nitrate reactions ; and 

 of 7. sindjarensis in the sodium-salicylate reaction. 



(5) The earliest period during the 60 minutes at 

 which the three curves are best separated to differen- 

 tiate the starches varies with the different reagents. 

 Approximately, this period occurs within 5 minutes in the 

 reactions with chromic acid, pyrogallic acid, nitric acid, 

 sulphuric acid, hydrochloric acid, potassium hydroxide, 

 potassium iodide, potassium suphocyanate, sodium hy- 

 droxide, sodium sulphide, sodium salicylate, calcium 

 nitrate, strontium nitrate, copper nitrate, cupric chlo- 

 ride, and mercuric chloride; at 15 minutes with chloral 

 hydrate, potassium sulphide, uranium nitrate, and 

 cobalt nitrate ; and at 60 minutes with barium chloride. 



REACTION-INTENSITIES OF THE HYBRID. 



This section treats of the reaction-intensities of the 

 hybrid as regards sameness, intermediateness, excess, and 

 deficit in relation to the parents. (Table A 33 and 

 Charts D 442 to D 462.) 



The reactivities of the hybrid are the same as those of 

 the seed parent with temperature, potassium sulphide, 

 and cobalt nitrate; the same as those of the pollen 



parent with iodine and sulphuric acid; the same as 

 those of both parents in the reactions with chromic acid, 

 hydrochloric acid, potassium iodide, potassium sulpho- 

 cyanate, and sodium hydroxide; intermediate with 

 chloral hydrate, nitric acid, sodium sulphide, uranium 

 nitrate, and strontium nitrate (in one being closer to 

 the seed parent, in two closer to the pollen parent, and 

 in two mid-intermediate) ; highest with pyrogallic acid, 

 potassium hydroxide, sodium salicylate, cupric chloride, 

 and mercuric chloride (in two being closer to the seed 

 parent, in two closer to the pollen parent, and in one 

 as close to one as to the other parent) ; and lowest with 

 the polarization, gentian violet, safranin, calcium nitrate, 

 copper nitrate, and barium chloride (in four being closer 

 to the seed parent, and in two closer to the pollen parent) . 



The following is a summary of the reaction-intensi- 

 ties : Same as seed parent, 3 ; same as pollen parent, 2 ; 

 same as both parents, 5; intermediate, 5; highest, 5; 

 lowest, 6. 



The influences of the seed and pollen parents seem to 

 be about equal, slightly in favor of the former. Inter- 

 mediateness is recorded in about one-fifth of the reac- 

 tions, and highness and lowness in about two-fifths. 



COMPOSITE CURVES OF EEACTION-INTENSITIES. 



This section treats of the composite curves of the 

 reaction-intensities, showing the differentiation of the 

 starches of Iris persica var. purpura, I. sindjarensis, and 

 7. pursind. (Chart E 33.) 



The most conspicuous features of this chart are : 



( 1 ) The marked closeness of all three curves through- 

 out, the most noticeable differences being in the reac- 

 tions with polarization, iodine, gentian violet, safranin, 

 temperature, potassium hydroxide, uranium nitrate, 

 cupric chloride, and barium chloride. In all other reac- 

 tions (17 out of 26) the curves are nearly or practically 

 identical, their closeness indicating very closely related 

 parental species, or more likely varieties. 



(2) The curve of 7. persica var. purpurea tends to 

 be lower than that of the other parent in the reactions 

 with polarization, temperature, sulphuric acid, potassium 

 sulphide, uranium nitrate, cupric chloride, and barium 

 chloride ; higher with iodine, gentian violet, and safranin ; 

 and the same or practically the same with chloral hydrate, 

 chromic acid, pyrogallic acid, nitric acid, hydrochloric 

 acid, potassium hydroxide, potassium iodide, potassium 

 sulphocyanate, sodium hydroxide, sodium sulphide, so- 

 dium salicylate, calcium nitrate, strontium nitrate, cobalt 

 nitrate, copper nitrate, and mercuric chloride. 



(3) The curve of the hybrid follows very closely the 

 curves of the parents, it being closer to or identical with 

 the curve of one or the other, or identical with both. 



(4) In 7. persica var. purpurea the very high reac- 

 tions with pyrogallic acid, nitric acid, sulphuric arid, 

 hydrochloric acid, potassium hydroxide, potassium iodide, 

 potassium sulphocyanate, sodium hydroxide, sodium sul- 

 phide reactions; the high reactions with polarization, 

 chromic acid, sodium salicylate, calcium nitrate, uranium 

 nitrate, strontium nitrate, copper nitrate, cupric chloride, 

 and meruric chloride ; the moderate reactions with iodine, 

 gentian violet, safranin, temperature; and the very low 

 reactions with chloral hydrate, potassium sulphide, cobalt 

 nitrate, and barium chloride. 



