156 



REACTION-INTENSITIES OF STARCHES. 



nently anionic. It might naturally be expected that if one 

 of the two reagents of either pair exhibits a higher reac- 

 tivity than the other member of the pair with a given 

 starch the same relationship in reaction-intensity should 

 be found in the reactions with other starches, but it will 

 be seen in each of these pairs of curves that there is not 

 only an absence of consistent relationship in so far as one 

 curve is always higher than the other, but also in other 

 respects, so that there is more or less marked inde- 

 pendence in the courses of the curves independence 

 quite as conspicuous as has been found in the compari- 

 sons of any pair of microscopic and macroscopic charac- 

 ters of the plants themselves. Thus, in Amaryllis bella- 

 donna with potassium hydroxide (Chart B 33) there 

 is complete gelatinization in 1 minute, and with sodium 

 hydroxide a not quite complete gelatinization in 3 min- 

 utes; while in the Brunsvigia Josephines reactions the 

 records with the same reagents are 98 per cent in 1 

 minute and 95 per cent in 15 minutes, respectively. 

 With the first starch the reagents exhibit but little dif- 

 ference, but with the second a marked difference, while 

 in both the potassium hydroxide is the stronger in its 

 actions. In other instances the values may be the same, 

 or the curves may be more or less separated, or inverted 

 so that the potassium hydroxide is the less effective. 



Passing from starch to starch it will be seen that 

 the separation of the curves observed in Brunsvigia is 

 as well marked in Hippeastrum. In Hcemanthus kath- 

 erince. the reactions of both reagents are very slow, almost 

 nil; but in H. puniceus there is a wide separation of the 

 curves, the potassium curve being high and the sodium- 

 hydroxide curve low. In Crinum moorei the two reac- 

 tions are very high and in C. zeylanicum very low. In 

 C. longifolium both are very high, but not so high as in 

 C. moorei. In C. moorei and C. zeylanicum there is in 

 each little difference in the potassium and sodium curves, 

 in the latter practically none ; but in C. longifolium the 

 curves are well separated. Subgeneric differentiation 

 here, as in the case of the species of llii'inanthus, is 

 quite marked. In Nerine the two curves are antipodal, 

 the potassium-hydroxide curve being very high and the 

 sodium-hydroxide curve very low, making the separation 

 exceptionally wide. In Narcissu-s the curves of both rea- 

 gents are low to very low, and the reactivities of the 

 reagents are in inverse relationship to what has been 

 heretofore noted, this starch being more responsive to 

 the sodium than to the potassium salt. In Lilium 

 the reactions with both reagents take place with such 

 rapidity that there is not satisfactory differentiation. 

 In Iris interesting differences in the curves are seen, and 

 so on with the other starches. Similar peculiarities will 

 be found in the comparisons of the curves of the pair 

 of acids. 



Comparing now the pairs of acid and base curves 

 (Charts B 15 and B 33) it will be noticed that notwith- 

 standing the opposite characters of the ions the curves 

 of the two charts bear in general resemblances that con- 

 form closely to a common type of curve ; that in each pair 

 one of the two reagents tends to be the more active, 

 or to have the same reactivity as the companion reagent 

 throughout most of the chart; that in each pair of 

 curves the quantitative relationships may be so altered 

 that there may be not only very variable degrees of dif- 



ferences in the extent of separation of the curves, but 

 also inversions and recrossings of the curves; and that 

 in the two charts the ordinates at which sameness of 

 reactivity-intensity of the reagents, higher reactivity 

 of one reagent over the other, inversion, recrossing, etc., 

 may have no correspondence. These facts demonstrate 

 an individuality of each reagent and each form of starch. 

 It will also be seen that while the two pairs of curves 

 are in general in their fluctuations in accord they may 

 not correspond in the extent of the variations. This 

 feature is conspicuous in Nerine, Narcissus, Iris, Gl/tili- 

 olus, Tritonia, and Begonia. Thus, in Nerine both of 

 the acid curves fall, the hydrochloric-acid curve for the 

 first two species (the values for the second and third be- 

 ing the same), and the nitric-acid curve for all three 

 species, making about the same difference between the 

 two curves for the first two species and a more marked 

 difference for the third species. The picture here is 

 entirely different from that of the potassium and sodium- 

 hydroxide chart. In Narcissus the hydrochloric-acid 

 curve is high and the nitric-acid curve very low; the 

 potassium and sodium-hydroxide curves are both very 

 low; the nitric-acid reaction is practically the same as 

 that of potassium hydroxide, somewhat lower than that 

 of sodium hydroxide, and markedly lower than that of 

 hydrochloric acid. In Iris both acid curves fall to the 

 level of moderate to low reactivity in the first three 

 starches, and in all practically the same; but in the 

 fourth starch both reactions are very high, the hydro- 

 chloric-acid reaction being distinctly higher than the 

 nitric-acid reaction. With the base reagents both curves 

 fall to the level of high to moderate reactivity in the 

 first three starches, and rise to high reactivity in the 

 fourth starch. The positions of the curves of the first 

 three starches differ entirely from those of the acids, 

 while those of the fourth starch are practically precisely 

 the same as those of the acids. In Gladiolus and Tri- 

 tonia both pairs of curves fall to the levels of low to 

 very low reactivity, the nitric-acid curve falling to a 

 lower level than the hydrochloric-acid curve; the hy- 

 droxide curves fall to an intermediate position, the so- 

 dium curve being lower than that of potassium. Be- 

 gonia shows striking similarities and dissimilarities: 

 In B. single crimson scarlet all four reagents act witli 

 great energy, gelatinization being complete in one min- 

 ute or less. In B. socotrana both acid curves fall, one 

 to the level of the line of demarcation of high to mod- 

 erate activity, and the other to very low reactivity; 

 whereas with the hydroxides the reaction with the potas- 

 sium salt is very rapid and is over in less than a minute, 

 while with the sodium salt it is very slow. Moroever, 

 in the acid reactions, while most of the starches show a 

 lower reactivity with nitric acid, B. socotrana shows a 

 markedly lower reactivity ; and in the potassium-sodium 

 chart most of the starches show a higher reactivity to 

 potassium than to sodium, the starch of B. socotrana 

 also showing this character. In other words, this spe- 

 cies is aberrant, as it were, in its reactions with the acids 

 in comparison with the reactions of the other Begonias 

 and most other starches, but in harmony in the potas- 

 sium and sodium reactions. In both Phaius and Miltonia 

 there is a reversal of the reaction-intensities of the two 

 acids, but not of the hydroxides, as compared with B. 



