BEGONIA. 



119 



TABLE A 36. 



Table A 3G shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals 

 (seconds and minutes). 



VELOCITY-REACTION CURVES. 



This section treats of the velocity-reaction curves of 

 the starches of Begonia single crimson scarlet, B. soco- 

 trana, and B. mrs. heal, showing quantitative differences 

 in the behavior toward different reagents at definite time- 

 intervals. (Charts D 505 to D 526.) 



The most conspicuous features of this group of curves 

 are: 



(1) The extraordinary variation of the relations of 

 the curves in the different charts : in some, all three curves 

 being practically identical or close together; in others, 

 two curves keeping close and the third well separated or 

 even separated to the extreme ; and in others, all three 

 being well separated from one another. These pecu- 

 liarities are due largely primarily to the remarkable 

 variations in the reactivities of B. socotrana in relation 

 to the different reagents (with one reagent being very 

 reactive and with another the reverse) ; and secondarily 

 to the almost uniformly very high reactivities of B. single 

 crimson scarlet (18 very high, 2 high, and 1 low), to- 

 gether with the marked variations in the relationships 

 of the hybrid to B. single crimson scarlet, the hybrid 

 being in many reactions identical or practically identical 

 with this parent and in others having varying degrees of 

 intermediateness, but being much closer, as a rule, to this 

 parent than to the other. Excepting the sulphuric-acid 

 and potassium-hydrate charts, in which the reactions of 

 all three starches are shown to occur with great rapidity, 

 there is a tendency to a well-marked or even extreme 

 separation of the parental curves, the starch of B. single 

 crimson scarlet showing, with one exception (barium 

 chloride), a very high to high reactivity, and that of 

 B. socotrana, with seven exceptions (chloral hydrate, 

 chromic acid, nitric acid, sulphuric acid, potassium hy- 

 droxide, potassium sulphide, and sodium salicylate) a 

 low or usually very low reactivity. 



(2) The higher reactivity of B. single crimson scar- 

 let than of B. socotrana with chloral hydrate, chromic 

 acid, pyrogallic acid, nitric acid, hydrochloric acid, potas- 

 sium iodide, potassium sulphocyanate, potassium sul- 

 phide, sodium hydroxide, sodium sulphide, sodium sali- 

 cylate, calcium nitrate, uranium nitrate, strontium ni- 

 trate, cobalt nitrate, copper nitrate, cupric chloride, 

 barium chloride and mercuric chloride, and the same 

 reactivities with sulphuric acid and potassium hydroxide. 

 There are small differences in the reactivities of the 

 parents with chloral hydrate, potassium sulphide, and 

 sodium salicylate, and from large to very large differ- 

 ences in the other reactions noted, excepting the sul- 

 phuric-acid and potassium-hydroxide reactions, in which 

 the two arc the same. 



(3) The tendency of the hybrid curves to be the 

 same or nearly the same as the curves of B. single crim- 

 son scarlet, or be of some degree of intermediateness, 

 usually closer to this parent, throughout the whole series 

 of reactions. (See following subsection.) 



(4) A period of early resistance followed by a com- 

 parative rapid reaction is conspicuous for its almost en- 

 tire absence. Such a period is suggested in the reactions 

 of the hybrid in the calcium-nitrate reaction, in B. single 

 crimson scarlet in the barium-chloride reaction, and in 

 B. socotrana in the chromic-acid reaction. 



(5) The earliest period during the 60 minutes at 

 which the three curves are best separated to differentiate 

 the starches varies with the different reagents. With 

 five exceptions this occurs in 5 minutes. The exceptions 



