134 



HISTOLOGIC PROPERTIES AND REACTIONS. 



Iodine: 

 C. lowianum, moderate, value 50. 



C. ebumeum, moderate, lighter than in 0. lowianum, value 45. 

 0. eburn.-low., moderate, the same as in C. lowianum, value 50. 

 Gentian violet: 

 C. lowianum, moderate to moderately deep, value 55. 

 C. ebumeum, light to moderately deep, slightly deeper than in 



C. lowianvun, value 57. 

 C. eburn.-low., light to moderately deep, the same as in C. lowi- 

 anum, value 55. 

 Safranin: 



C. lowianum, moderate to moderately deep, value 52. 



C. ebumeum, moderate to moderately deep, slightly deeper than 



in C. lowianum, value 55. 

 C. eburn.-low., moderate to moderately deep, the same as in C. 



lowianum, value 52. 

 Temperature : 



C. lowianum, in the majority at 58 to 60°, in all at 62 to 63°, 



mean 62.5°. 

 C. ebumeum, in the majority at 58 to 59.5°, in all at 65 to 66.5°, 



mean 65.76°. 

 C. eburn.-low., in the majority at 61 to 63°, in all but rare grains at 



67 to 68°, mean 67.5°. 



C. lowianum exhibits a higher reactivity than the 

 other parent in the polarization, iodine, and temperature 

 reactions, and a lower reactivity in the gentian- violet and 

 safranin reactions. The hybrid has the same reactivities 

 as C. lowianum in the reactions with polarization, iodine, 

 gentian violet, and safranin, but has a lower reactivity 

 than either parent with temperature, in which it is nearer 

 to C. ebumeum. 



Table A 44 shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals (sec- 

 onds and minutes). 



Velocity-reaction Curves. 



This section treats of the velocity-reaction curves of 

 the starches of Cymlidium lowianum^ C. ebumeum^ and 

 C. eburneo-lowianum, showing the quantitative difference 

 in the behavior toward different reagents at definite time- 

 intervals. (Charts D 616 to D 618.) 



The reactions with the various reagents, with rare 

 exceptions, occur with such rapidity that such differences 

 as may have been noted are not conclusive, all three 

 starches being gelatinized completely or practically com- 

 pletely within a minute or two, and often within 15 to 

 30 seconds. Where no differences are recorded between 

 the reactions of the parents those of the hybrid may be 

 distinctly different, as in the chloral-hydrate, pyrogaJlic- 

 acid, and barium-chloride reactions, especially in the 

 last. For the reason stated, only the curves of these 

 three reactions have been charted. 



Eeaction-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 44 and 

 Charts D 616 to D 618.) 



The reactivities of the hybrid are the same as those 

 of the seed parent in the reactions with polarization, 

 iodine, gentian violet, and safranin ; the same as those of 

 the pollen parent in none; the same as those of both 

 parents with sulphuric acid, hydrochloric acid, potas- 

 sium hydroxide, potassium iodide, potassium sulphocya- 

 nate, potassium sulphide, sodium hydroxide, sodium sul- 

 phide, and strontium nitrate, in all of which the reactions 

 are too rapid for differentiation; intermediate or high- 

 est in none; and the lowest with temperature, chloral 

 hydrate, chromic acid, pyrogallic acid, nitric acid, so- 

 dium salicylate, calcium nitrate, cobalt nitrate, copper 

 nitrate, cupric chloride, barium chloride, and mercuric 

 chloride (in 1 being closer to the pollen parent, and in 

 12 as close to one as to the other parent) . 



The following is a summary of the reaction-intensi- 

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



