REACTION-INTENSITIES WITH EACH AGENT AND REAGENT. 



157 



socotrana. Additional c parisons of the data of these 



charts will bring oul manj interesting facts. 



The potassium sulphide and sodium-sulphide chart 

 ( t lharl B 34) bears in certain ! n resem- 



blances to the hydroxide chart (Chart B33) than to the 

 acid chart (Chart B 15), and iii other respects the re- 

 . thus indicating thai the alteration of the hydrox- 

 ides into the sulphides has yielded reagents which give 

 rise to reactions thai suggest the presence of both active 

 cations and anions, in contradistinction to the reactions 

 of the hydroxides and acids which arc pre-eminently 

 lie and anionii . respectively. These sulphide reac- 

 tions varv in intensity in both directions to almost the 

 extreme limits of the abscissae, from the extremely high 

 reactivities of potassium sulphide that arc recorded in 

 LUhim , Begonia, and Phaius in which complete gelatiniza- 

 tion occurs in 2 minutes or [ess, to the extremely low 

 reactivities in Hippeastrum, Hcemanthus, Crinum, etc., 

 where 5 per cent or less is gelatinized in ti 11 minutes, 

 The deviations of these curves from the acid and base 

 curves arc much more marked than the variations of the 

 curves themselves, and the quantitative difference 

 tween the curve- tend to be more marked and erratic, 

 and inversions to be more frequent, than in the acid 

 and base curves. In Nerine there occurs in the sulphide 

 curves, as in those of the hydroxide, an inversion, in 

 both charts the potassium salt is the stronger. In Iris 

 there is a marked separation of the curves, as was found 

 to be the case with one exception in the hydroxide reac- 

 tions; but in three of the starches there was no separa- 

 tion of the acid curves. In Begonia socotrana the curves 

 are less like those of the bases than of the acids, while 

 in Mil Inn i:i they stand apart from both base and acid 

 curves. The wide separation of the sulphide curves in 

 Amaryllis is very conspicuous in comparison with the 

 small separation of the base curves and the al sence of 

 ation of the acid curves. Similar peculiarities 

 will he found in the reactions of these three pairs of 

 reagents with other starches. 



The potassium-iodide and potassium-sulphocyanate 

 reactions (Chart B35) hear, on the whole, far closer 

 resemblances to the hydroxide reactions than to th( 

 or sulphide reactions. In contradistinction to the sul 

 phides these reagents contain acid radicals that are 

 probably almost inert. Comparing this chart with the 

 base chart (Chart B 33), the most noticeable differences 

 will be found in the reactivities with Amaryllis, Bruns- 

 vigia, Hcemanthus puniceus, Nerine, Iris, Begonia, 

 Phaius, and MUtonia. Amaryllis and Brunsvigia 

 exhibits practically no difference in the potassium-iodide 

 or potassium-sulphoi yai ate n actions, but Amaryllis and 

 Brunsvigia are differentiated from each other by both 

 reagents, both starches reacting more readily with po- 

 tassium iodide than with the other reagent. In Hceman- 

 thus puniceus, while these rea ;ents do not differ in their 

 reactivities, potassium hydroxide yields a markedly dif- 

 ferent result from that of sodium hydroxide. In Nerine 

 reactivity with the iodide is very low and with the sul- 

 phocyanate low; while in the hydroxide reaction- thosi 

 with potassium hydroxide are very high and those 

 with sodium hydroxide very low. In Iris the 

 sium iodide reactions are very much lower in the first 

 three Irid.- and somewhat lower in the fourth; while 



in the hydroxidi two there are very marked 



differences, in one no difference, and in another a 

 marked difference, the potassium reactions being the 

 lower when difference exists. In Begonia the iodide 

 and sulphocyanate reactions show very little difference, in 

 /.'. sing ;reat 



nd in /.'. socotrana with great slow i I 

 iodide being practically inert; while in the hydroxide 

 reactions both rea with 



/;. single ci arlet, potassium hydroxide acts with 



equal vigor, hut sodium hydroxide with low into i 

 with /:. socotrana. In Phai the 



iodide and the sulphocyanate show diffen 



i aese genera and <>■ I wi en the m jenus, the 



iodide being less active than 1 While in 



both Phaius and MUtonia marked di ' st be- 



tween the reaction-intensities of the iodide and the 

 sulpho . there an . small differences 



between the intensities of the hydroxides. 



The curve of sodium salicylate (( hart B 36) -\ 

 . as before stated, and therefore is not compai 

 as in the foregoing instances, with that of any other 

 n ■ -iit . 



Calcium nitrate and strontium nitrate (Chart B 

 exhibit differences that are most pronounced in Bruns- 

 vigia, Crinum, Nerine, and MUtonia. The calcium curve 



appears f Tes] I more particularly with the curves 



of potassium iodide, potassium Bulphocyanate, and so- 

 dium hydroxide; while the strontium curve appears to 

 be more closely related to the curves of uranium nitrate. 

 copper nitrate, cupric chloride, and mercuric chloride. 

 All of the latter curves appear to be very closely n 

 ommon type, which suggests that the reactioi 

 so far as the latter depend upon the reagents, are due 

 essentially to differences in the basic ions or cations. 



Differentiation of Subgeneric Groups. — There is 

 probably no feature of I hese cl arts more prominent or of 

 greater value in proof of the worth of the gelatinization 

 method in the differentiation of starches from different 

 sources than the constancy and definiteness in similar 

 and dissimilar directions of the differen 

 generic representatives. "Hcemanthus katherinae and If. 

 puniceus are, from the standpoint o the systematist, at 

 most well bul from the E this 



research they are probably to be regarde I as n 

 tives of well-defined subgeneric groups. Had tin- m 

 subgeneric differentiation been indicated by the reac- 

 tions of a single or an occasional reagent it might natur- 

 ally he regarded as being accidental, hut it is evident 

 throughoui the charts of the reactions of the 21 reagents, 

 except the chloral-hydrate and sodium-salicj 

 tions. T! ne species is as definitely and widely differ- 

 entiated from the other a- are genera in general, with 

 the exception only of the el liolus and 



Tritonia. While at the end of 60 minutes there is only 

 slight and questionable differentiation in the chloral- 

 hydrate re and in the sodium-salicylate rea 

 no differentiation, there are differences of importance 

 i during the progress of the reactions (Charts "P tor, 

 and D11S). The hardy and tender Crinums are with 

 every reagent markedly differentiated, hut by some to a 

 ree than by other-. Tl if the two 

 hardy Crinums are in all oJ 



