110 



HISTOLOGIC PROPERTIES AND REACTIONS. 



progress of gelatiuization is too fast or too slow for 

 differentiation; intermediate with chromic acid, and 

 closer to that of the seed parent; highest with iodine, 

 temperature, chloral hydrate, and sodium salicylate (in 

 one being nearer the seed parent, and in three nearer the 

 pollen parent) ; and lowest with polarization, gentian 

 violet, safranin, pyrogallic acid, hydrochloric acid, po- 

 tassium hydroxide, potassium iodide, potassium sulpho- 

 cyanate, potassium sulphide, sodium hydroxide, sodium 

 sulphide, calcium nitrate, uranium nitrate, strontium 

 nitrate, copper nitrate, cupric chloride, and mercuric 

 chloride (in five being closer to the seed parent, in nine 

 closer to the pollen parent, and in three being as close 

 to one as to the other parent). 



The following is a summary of the reaction-intensi- 

 ties: Same as seed parent, 0; same as pollen parent, 1; 

 same as both parents, 3; intermediate, 1; highest, 3; 

 lowest, 17. 



Three features stand out most conspicuously : the 

 more marked influence of the pollen parent on the proper- 

 ties of the starch of the hybrid, the remarkably strong 

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

 the curves of the parents, especially to be below, and the 

 almost entire absence of intermediateness. 



COMPOSITE CURVE OF THE REACTION-INTENSITIES. 



This section treats of the composite curve of the 

 reaction-intensities, showing the differentiation of the 

 starches of Iris cengialti, I. pallida queen of may, and 

 I. mrs. alan grey. (Chart E 32.) 



The most conspicuous features of this chart are : 



(1) The closeness of all three curves, excepting in 

 the reactions with chloral hydrate, calcium nitrate, ura- 

 nium nitrate, strontium nitrate, copper nitrate, and 

 cupric chloride, in all of which, excepting the first, the 

 separation is within comparatively narrow limits, and in 

 all the separation is due in a large measure or solely 

 to the hybrid curve going above or falling below the 

 parental values, a tendency that was also recorded in 

 the histologic and qualitative peculiarities and the reac- 

 tion-intensities expressed by light, color, and temperature 

 reactions of this summary. 



(2) The curve of Iris cengialti tends to be higher 

 than that of /. pallida queen of may in the reactions with 

 polarization, iodine, temperature, nitric acid, sulphuric 

 acid, potassium iodide, calcium nitrate, uranium nitrate, 

 strontium nitrate, copper nitrate, and cupric chloride; 

 lower with gentian violet, safranin, chloral hydrate, and 

 pyrogallic acid ; and the same or practically the same 

 with chromic acid, sulphuric acid, potassium hydroxide, 

 potassium sulphocyanate, potassium sulphide, sodium hy- 

 droxide, sodium sulphide, cobalt nitrate, barium chloride, 

 and mercuric chloride. In several of the reactions where 

 the curves differ they are so close as to be probably within 

 the limits of error of experiment, as in the reactions with 

 temperature, pyrogallic acid, nitric acid, hydrochloric 

 acid, potassium iodide, calcium nitrate, uranium nitrate, 

 copper nitrate, and cupric chloride. Charts D 421 to 

 I' Ml are to be taken with these data in determining 

 differences in reactivity, but the differences will doubt- 

 less be found to hold excepting for slight variations. 



(3) The curve of the hybrid is variable in its relations 

 to the parental curves, commonly exhibiting either an 

 inclination to be the same as the curve of one or both 

 parents or to be above or below, but not to intermediate- 

 ness. In Chart D 442 in the chromic-acid reactions there 

 was definite intermediateness up to the 45-minute rec- 

 ord, and there were also transient intermediate tendencies 

 in other reactions (see preceding section) ; but these are 

 not apparent in this chart, owing to inherent defects of 

 construction. 



(4) In 7. cengialti, the very high reactions with 

 sulphuric acid, potassium sulphocyanate, and sodium 

 salicylate; the high reactions with polarization, chromic 

 acid, and sodium hydroxide; the moderate reactions with 

 iodine, gentian violet, safranin, hydrochloric acid, potas- 

 sium hydroxide, and potassium iodide ; the low reactions 

 with temperature, chloral hydrate, pyrogallic acid, nitric 

 acid, sodium sulphide, strontium nitrate, copper nitrate, 

 and cupric chloride; and the very low reactions with 

 potassium sulphide, uranium nitrate, cobalt nitrate, 

 barium chloride, and mercuric chloride. 



(5) In 7. pallida queen of may the very high reac- 

 tions with sulphuric acid and sodium salicylate ; the high 

 reactions with polarization, chromic acid, potassium sul- 

 phocyanate, and sodium hydroxide; the moderate reac- 

 tions with iodine, gentian violet, safranin, nitric acid, 

 hydrochloric acid, potassium hydroxide, and potassium 

 iodide ; the low reactions with temperature, chloral hy- 

 drate, pyrogallic acid, sodium sulphide, calcium nitrate, 

 strontium nitrate, copper nitrate, and cupric chloride ; 

 and the very low reactions with potassium sulphide, ura- 

 nium nitrate, cobalt nitrate, barium chloride, and mer- 

 curic chloride. 



(6) In the hybrid, the very high reactions with 

 sulphuric acid and sodium salicylate; the high reactions 

 with chloral hydrate, chromic acid, potassium sulpho- 

 cyanate, and sodium hydroxide reactions ; the moderate 

 reactions with polarization, iodine, gentian violet, safra- 

 nin, and potassium hydroxide ; the low reactions with tem- 

 perature, pyrogallic acid, nitric acid, hydrochloric acid, 

 potassium iodide, sodium sulphide, calcium nitrate, and 

 strontium nitrate ; and the very low reactions with potas- 

 sium sulphide, uranium nitrate, cobalt nitrate, copper 

 nitrate, cupric chloride, barium chloride, and mercuric 

 chloride. 



Following is a summary of the reaction-intensities : 



33. COMPARISONS OF THE STARCHES OF IRIS 

 PERSICA VAR. PUKPUREA, I. SINDJARENSIS, AND 

 I. PURSIND. 



In histologic characteristics, polariscopic figures, reac- 

 tions with selenite, reactions with iodine, and qualitative 

 reactions with the various chemical reagents all three 

 starches exhibit properties in common in varying degrees 

 of development, the sum of which in case of each starch 

 is distinctive of the starch. The starch of Iris sind- 

 jarensis in comparison with that of 7. persica var. pur- 

 purca contains many more compound grains, all of the 

 same types but in different proportions; and the grains 

 are much more regular in form. The hilum is not so often 

 or so deeply and extensively fissured; there is an ab- 

 sence of a single fissure in compound grains which passes 

 through all of the hila, as was noted in the other parent ; 

 and eccentricity is usually greater. The lamellae are not 

 so coarse and are more regular, and the number is larger. 

 The size is smaller. In the polariscopic, selenite, and 

 qualitative iodine reactions there are various differences. 

 In the qualitative reactions with chloral hydrate, hydro- 

 chloric acid, potassium iodide, sodium hydroxide, sodium 

 salicylate, and mercuric chloride there are also many 

 differences which on the whole definitely individualize 

 each parent. The starch of the hybrid in comparison 

 with the starches of the parents contains a less number 



