356 



STARCHES OF GRAMINACE^. 



Diffcrenliation of the Starches of the Genus Zea. — Continued. 

 Effecto of Variods Reagents. — Continued. Effects of Various Reagents. — Continued, 



Reaction with Chromic Acid. — Continued. 



Z. mays var. saccharata: 



Stowell's Evergreen. Begins immediately; complete 



in a few in a minute, in all in 3 minutes. 

 Black Mexican. Begins immediately; complete in 



some in 20 seconds, in all in 50 seconds. 

 Golden Bantam. Begiiis immediately; complete in 



some in 25 seconds, in all in 70 seconds. 



Reaction milh Pyrogallic Acid. 



2. mays var. everta: 



Ciolden Queen. Begins immediately; complete in all 



in 35 seconds. 

 White Rice. Begins immediately; complete in all in 



45 seconds. 

 Z. mays var. indurala: 



North Dakota. Begins immediately; complete in 



some in 30 seconds, in all in 1 J^ mmutes. 

 Compton's Early. Begins immediately; complete in 



a few in 30 seconds, in all in 2 minutes. 

 Z. mays var. indentata: 



Early Learning. Begins immediately; complete in 



a few in 30 seconds, in all in 2 minutes. 

 Hickory King. Begins immediately; complete in a 



few in 30 seconds, in all in a minute. 

 Z. mays var. saccharata: 



StowcU's Evergreen. Begins immediately; complete 



in many in 30 seconds, in all in 2 minutes. 

 Black Mexican. Begins immediately; complete in 



all in 40 seconds. 

 Golden Bantam. Begins immediately; complete in 



a few in 30 seconds, in all in a minute. 



Reaction with Ferric Chloride. 



Z. mays var. everla: 



Golden Queen. Begins immediately; complete in 



most in 4 minutes, in all in 10 minutes. 

 White Rice. Begins immediately; complete in most 



in 3}^ minutes, in all in 10 minutes. 

 Z. mays var. indurala: 



North Dakota. Begins immediately; complete in 



most in 6 minutes, in all in 15 minutes. 

 Compton's Early. Begins immediately; complete in 



most in 5 minutes, in all in 12 minutes. 



Reaction mth Ferric Chloride. — Continued. 



Z. mays var. indentata: 



Early Learning. Begins immediately; complete in 



most in 5 minutes, in all in 12 minutes. 

 Hickory King. Begins immediately; complete in 



most in 3 minutes, in all in 8 minutes. 

 Z. mays var. saccharata: 



Stowell's Evergreen. Begins immediately; complete 



in most in 5 minutes, in all in 10 minutes. 

 Black Mexican. Begins immediately; complete in 



most in 4 minutes, in all in 10 minutes. 

 Golden Bantam. Begins immediately; complete in 



most in 4 minutes, in all in 10 minutes. 



Reaction iviih Purdy's Solution. 



Z. mays var. everla: 



Golden Queen. Begins immediately; complete in 



one-third in 30 minutes; but little further reaction 



in an hour. 

 White Rice. Begins immediately; complete in one- 

 third in 30 minutes, but little further reaction in 



1 hour. 

 Z. mays var. indurala: 



North Dakota. Begins immediately; complete in 



rare grains in 30 minutes, in very few in an hour. 

 Compton's Early. Begins immediately; complete 



in rare grains in 30 minutes, in very few in an 



hour. 

 Z. mays var. indentata: 



Early Leaming. Begins immediately; complete in 



one-fifth in 30 minutes, little further change in 



an hour. 

 Hickonr King. Begins immediately; complete in 



one-fifth in 30 minutes, very incomplete in an 



hour. 

 Z. mays var. saccharata: 



Stowell's Evergreen. Begins immediateljr; complete 



in one-tenth in 30 minutes, but very incomplete 



in 1 hour. 

 Black Mexican. Begins immediately; complete in 



four-fifths in 30 minutes, but incomplete in an 



hour. 

 Golden Bantam. Begins immediately; complete in 



half in 30 minutes, but incomplete in 1 hour. 



NOTES ON THE STARCHES OF ZEA. 



The com starches differ so little and so indefinitely in their gross microscopical characteristics 

 that it is not possible to differentiate one from another in this way, and it is doubtful if even de- 

 tailed histological examination, unless possibly with the assistance of reagents, would be of real 

 service. The curves of the reaction-intensities, on the other hand, show not only specific differen- 

 tiations of one variety from another, but also a more or less positive grouping that is in accord 

 with that of the agriculturist. Inasmuch as all of the corn starches are products of varieties or forms 

 of a single species, but little differences, upon general principles, should be expected to be found 

 among the different specimens; yet it will be noted that not only are no two curves identical, even 

 in members of the same agricultural group, but also that the composite curves of each group must 

 differ in characteristic ways from those of the others. While some of the differences are slight and 

 fall within the limits of error of experiment, they are as a whole distinctly diagnostic. In the polar- 

 ization reactions there are small and unimportant differences, except in the Black Mexican variety, 

 in which polarization is distinctly lower than in the others, but this may be accounted for in the 

 presence of dark coloring matter which clung tenaciously to the starch-grains. The intensities of 

 the iodine reactions are the same throughout, except in the case of the everlce, in both of which the 

 reaction is slightly less than in the other groups. In the gentian-violet reactions there is distinct 

 evidence of grouping, the reactions of all of the saccharatce being distinctly lower than the others, 

 which are about the same. With safranin there is an obvious grouping, the reactions with the 



