REACTIO\-IMKN-1T11> WITH i: \< II AOENT AND REAGENT. 



L6I 





Terr nuirh higher sensitivity than tin- former; while 

 . hydroxide there are three gradation* >f 



,\ity. T:. -n* of /n.t prrxifa var. purpurea 



differentiate it from the first three member* of tin* 



Another feature is aeen in the very striking 



dirtYreiKvs in / in the first Hrgonia both refte- 



. . TV hi^'h and the same, while in the second the 



-lum-hydroudc reaction U similarly high and the 

 odium-hydroxide reaction U low and far separated from 

 tin- former. 



.in sulphide and sodium sulphide (Chart 

 B 3 1 ) elic it reactions which at a whole are quite different 

 from those recorded in the preceding chart*, bnt are 



lu-levs in entire support of the fundamental pecu- 

 liarities that have U-.-n found to be set forth by the 



in* of each pair of reagents thus far studied that 

 it, an inde|N-mlencc of each reagent in its reactions that 

 is due to Uitli .<iini-iitr.it ion and kind of solute; an inde- 

 pendence of the reactions of each starch that U dependent 

 rences in stereoisomeric forms; and an imle- 



nce of the course of each curve to such a degree 



that there may not only be most variable quantitative 



different?* hut also inversion, yet with a manifest ten- 



nforming with the peculiarities of a prototype 



(say the nitric-acid curve). 1'robably the first feature 



that will attract attention is the very marked differences 



in tin- behaviors of Amaryllit and Brunsrigia with these 



. reagent*, the former exhibiting a very 



hurh reactivity with potassium sulphide and a moderate 



with sodium sulphide, thus showing a very 



difference in reactivity, there being 97 per cent of 



the total starch of Amaryllis gelatinized in 3 minutes 



and only 91 per cent of the total starch of Bruntvigia 



minutes; whereas with sodium sulphide the reac- 



of both starches are very nearly the same, 90 and 

 96 per cent, respectively, in 60 minutes being recorded, 

 Amaryllis throughout the course of the reaction showing 

 only slightly leas reactivity than Bruiuvigia. 



It will be noted that the two curves here are entirely 

 different from those of the three preceding charts (Charts 

 I'. .<!. I'. :<2, and B33), which also so differ from each 

 other that each chart is very definitely individualized. 

 The reactions of the sulphides are the same or practically 

 the same in Brunsvigia Joseph intr, Ilippfastrum titan. 

 II. otfultan, Ilirmanthux josephimr, Crinum teylanicum, 

 I. ilium martagon, L. tenuifolium, L. chalcedonieum, L. 

 pardalinum, and Begonia tingle crimson tcarlet. The 

 potassium-sulphide reactions are higher in Amaryllu bel- 

 ladonna, llcemanthus puniceut, Kerine crispa, N. botc- 

 deni, A', sarnirnfi* var. corusca major, Begonia tocotrana, 

 and Pkaiut grandifolius ; and lower in llippeattrum 

 daones, Crinum moorri, C. lonyifolium. Narcissus late-tin 

 grand monarque, Irit iberioa, /. trojana. I. cengialti, I. 

 persica var. purpurra. Gladiolus tritlit, Triionia potlsii, 

 and .Miltuniii rrxillarin. For the most part the curves are 

 well separated, this feature being particularly accen- 

 tuated in Amaryllis belladonna, Crinum moorti, fferine 

 crispa, Irit persica var. purpurra, and Hrgonia tocotrana. 



inlhus katherina and //. puniceut are not nearly 

 so well differentiated as in the preceding charts; the 

 hardy and tender Crinnms are well differentiated, as 

 in the previous pairs of reactions. The I rids show nearly 

 the same reactivities with potassium sulphide, while three 



show nearly the same reactivities with sodium sulphide, 

 luit higher than with potassium sulphide, and one a very 

 much higher reactivity than the first three with sodium 

 *ul|>hidc and a corresponding difference in relation t 

 potassium sulphide, showing a marked subgeneric sub- 

 division such as was noted with other reagents. In 

 Oladiolut and Tritonia the potassium-sulphide curves are 

 well IM-IMW the sodium-sulphide curves, the difference in 

 each being about the same. In Begonia the differentia- 

 tion of the two starches is very striking. In I'haius and 

 Miltonia the generic differences are pronounced, not 

 only in regard to the degree of separation of the curves, 

 but also in respect to the inversion of the curves. The 

 high reactivities shown in Amaryllit belladonna, Nerine 

 critpa, and Begonia socotrana with potassium sulphide 

 in comparison with the moderate to very low rc.-u ti-.itic- 

 with the other reagent, together with the very opposite 

 in Crinum moorri, Iris persica var. purpurea, and Mil- 

 tonia bleuana, are striking manifestations of differences 

 in the molecular constitution of starches from different 

 plant sources. 



The reaction-intensities of potassium iodide and po- 

 tassium sulphocyanate (Chart B35) present very much 

 closer relationships than do those of any of the pairs of 

 reagents thus far considered, yet here also are found 

 the fundamental peculiarities that have characterized all 

 of the comparisons brought out in the preceding churl*. 

 The reactivities of these reagents are the same in llaman- 

 thut kafhrrinir, Crinum moorei, C. teylanicum, C. longi- 

 folium, Lilium martagon, L. tenuifolium, L. chalcedoni- 

 cum, L. pardalinum, and Begonia tingle crimson scarlet. 

 The reactions of potassium iodide are higher than those 

 of potassium sulphocyanate in Amaryllis belladonna and 

 Brunsrigia Joseph inct, and IOWA- with all of the remain- 

 ing starches, except the group noted. The curves show 

 for the most part a marked concordance in their up- 

 and-down movements, but the degree of separation < f 

 the curves is quite variable and there are inversions only 

 of Amaryllit and Brunsrigia. 



A comparative examination of the curves of the reac- 

 tions of sodium hydroxide and sodium salicylate (('hart 

 B 36) brings out one very exceptional feature that is 

 associated with the latter reagent, and various featun 

 that are in harmony with characteristics that are com- 

 mon to the other charts. The marked limitations of the 

 reactions of sodium salicylate are most striking and 

 peculiar to this reagent. In only two reactions (those 

 with Crinum jrylanicum and Begonia tingle crimton 

 tcarlet) is there a departure from the narrow limits of 

 the upper six abscissa (a trifle more than one-fourth 

 of the highest and lowest limits of reaction-intensities). 

 This limitation greatly restrict* the value of the reagent 

 in the differentiation of starches from different plant 

 sources, yet there are in some instance* marked to very 

 marked differentiation, especially of subgeneric groups. 

 The differences in the reactions of the two specie* of 

 Htrmantkut are not of themselves sufficient to definitely 

 indicate subgeneric division, but rather well-separated 

 species; in Crinum the two hardy forms are well differ- 

 entiated from the tender form; in Iru the first three 

 stand definitely apart from the fourth ; and in Begonia 

 there are striking difference* between the two starches. 



