52 



HISTOLOGIC PROPERTIES AND REACTIONS. 



VELOCITY-REACTION CURVES. 



This section treats of the velocity-reaction curves 

 of the starches of Crinum moorei, C. zeylanicum, and 

 C. hybridum, j. c. harvey, showing the quantitative 

 differences in the behavior toward different reagents at 

 definite time-intervals. (Charts D 127 to D 147.) 



Among the most conspicuous features of this group 

 of curves are : 



(1) The marked differences between the curves of 

 the starch of C. moorei on the one hand and those of 

 C. zeylanicum and the hybrid on the other. The former 

 is in nearly all reactions quick-reacting, while the latter 

 is the reverse. In only 6 of the 21 reactions the former 

 (including the reactions with chloral hydrate, chromic 

 acid, pyrogallic acid, sulphuric acid, sodium salicylate, 

 and barium chloride) is there an evident approximation 

 of the curve of C. moorei to that of the other parent 

 or the hybrid. In the reactions with chloral hydrate 

 and barium chloride the approach of the curves is owing 

 essentially (chloral hydrate) or solely (barium chloride) 

 to the relatively low degree of reactivity of C. moorei 

 with these reagents as compared with others; in those 

 with pyrogallic acid and sulphuric acid to 1 the relatively 

 very high reactivity of C. zeylanicum and C. hybridum 

 j, c. harvey; and in those with chromic acid and sodium 

 salicylate to the combined relatively low reactivity of 

 C. moorei and relatively high reactivity of C. zeylanicum 

 and C. hybridum j. c. harvey. 



(2) The marked early period of resistance followed 

 by a moderately rapid to a rapid reaction exhibited by 

 C. zeylanicum and the hybrid in the reactions with 

 chromic acid, pyrogallic acid, sulphuric acid, hydro- 

 chloric acid, and sodium salicylate are in striking con- 

 trast with the very marked continued resistance that is 

 exhibited by the records of the remaining 16 reagents 

 during the entire 60-minute interval. 



(3) A comparison of the differences in the course of 

 the reaction-curves will elicit many points of interest. 

 Thus, taking the acid group, and comparing the charts 

 for chromic acid, pyrogallic acid, nitric acid, sulphuric 

 acid, and hydrochloric acid, it will be seen, at a glance, 

 that they so differ that the influence of any one reagent 

 can readily be distinguished from those of others ; like- 

 wise, those of potassium sulphide and sodium sulphide. 

 On the other hand, three groups of charts, including 

 those of (a) potassium hydroxide and sodium hydrox- 

 ide, (6) calcium nitrate, uranium nitrate, strontium 

 nitrate, cobalt nitrate, copper nitrate, cupric chloride, 

 and mercuric chloride, and (c) nitric acid, potassium 

 hydroxide, potassium iodide, potassium sulphocyanate, 

 sodium hydroxide, and potassium sulphide are in each 

 case closely alike, notwithstanding wide differences in 

 the characters of the reagents. 



(i) The earliest period during the 60 minutes at 

 which the reaction-curves are farthest apart, and hence 

 the best period for the differentiation of the three 

 starches, varies markedly with the different reagents. 

 Approximately, this optimal period occurs at the end 

 of 15 minutes in the reactions with nitric acid, sulphuric 

 acid, potassium iodide, and sodium hydroxide ; 30 min- 

 utes with chromic acid, pyrogallic acid, hydrochloric 

 acid, potassium hydroxide, sodium sulphide, and sodium 

 salicylate; and 60 minutes with chloral hydrate, potas- 

 sium sulphocyanate, potassium sulphide, calcium ni- 

 trate, uranium nitrate", strontium nitrate, cobalt nitrate, 

 copper nitrate, cupric chloride, barium chloride, and 

 mercuric chloride. 



EEACTION-INTENSITIES OF THE HYBRID. 

 This section deals with the reaction-intensities of the 

 hybrid as regards sameness, intermediateness, excess and 



