l.-.li 



REACTION-INTENSITIES OF STARCHES. 



. 1 1 mighl oaturally be expected that if one 

 two reagents of either pair exhibits a higher i ai 

 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 relal ionship in so Ear as one 

 curve is always higher than the other, bu1 also in other 



Is, so that there is mere or less marked inde- 

 iii 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 B33) there 

 is complete gelatinization in 1 minute, and with sodium 

 hydroxide a qoI 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 lie 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 hath- 

 erina the reactions of both reagents are very slow, almost 

 nil; but in //. punici us 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 



igifolium both are very high, but not so high as in 

 ( '. moorei. In (■'. moorei and ('. zeylanicum there is in 

 each little difference in the potassium and sodium curves, 

 in the latter practically none; but in 0. longifolium the 

 curves are well separated. Subgeneric differentiation 

 here, as in the case of the species of Hcemanihus, is 

 quite marked. Jn Nerine the two curves arc antipodal, 

 the potassium-hydroxide curve being very high and the 

 sodium-hydroxide curve very low, making the separation 

 exceptionally wide. In Narcissus the curves of both rea- 

 are lovi to very low, and the reactivities of the 

 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 thai there is nol satisfactory differentiation. 

 In Iris interesting differences in the curves are seen, and 

 th the other starches. Similar peculiarities will 

 be found in the comparisons of the curves of the pur 



ids. 

 Comparing now the pairs of acid and base curves 

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

 ding the oppo b ch irai ters *■( 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 

 i broughoul most of the i hai I ; that in each pair i 

 curves the quantita lationships may be 30 altered 



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



ferences in the extent of separation of the curves, but 

 al o inversions and recrossings of the curves; and that 

 in the two charts the ordinate's at which 

 reactivity-intensity of the reagent-, higher reactivity 



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

 may have no correspondence. These facts demonstrate 



an individuality of each reagenl and each form of .-larch. 

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

 are in general in their fluctuations in accord thej ma] 

 not correspond in the extent of the variation-. This 

 feature is conspicuous in Nerine, Narcissus, Iris, Gladi- 

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

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

 first two species (the value- 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 Tn- 

 lonia 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 curve- fall to an intermediate position, the so- 

 dium curve being lower than that of potassium. Be- 

 gonia shows striking similarities and dissimilarities: 

 In /»'. single crimson scarlet all four reagents act with 

 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 mosl of the starches show a 

 lower reactivity with nitric acid, /•'. socotrana shows a 

 markedly lower reactivity; and in the potassium-sodium 

 chart mosl of the starches show a higher reactivity to 

 potassium than to sodium, the standi of /;. socotrana 

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

 cies is aberrant, as it were, in its reactions v\ ith the acids 

 in comparison with the reactions of the other I'.ogoiiias 

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

 sium and sodium reactions. In both Phaius and Mi 



is a reversal of the reaction-intensities of the two 

 acid-, but not of the hydroxides, as compared with B. 



