COMPOSITION IN SUCCESSIVE STAGES. 211 



(33 | ,) is found in the 4th; in the upper leaves, (38 | ,) in 

 the 2d period. 



The apparent diminution in amount of fiber is due in 

 all cases to increased production of other ingredients. 



2. Fat and Wax are least abundant in the stem. Their 

 proportion increases, in general, in the upper parts of the 

 stem, as well as in the later stages of its growth. The 

 range is from 0.2 | to 3| . In the ear the proportion in- 

 creases from 2| to 3.7 | . In the leaves the quantity is 

 much larger and is mostly wax. The smallest proportion 

 is 4.8 | , which is found in the upper leaves, when the 

 plant is ripe. The largest proportion, (10 | ,) exists in 

 the lower leaves, at the time of blossom. The relative 

 quantities found in the leaves undergo considerable varia- 

 tion from one stage of growth to another. 



3. Non-nitrogenous matters, other than fiber, starch, 

 sugar, etc.* undergo great and irregular variation. In 

 the stem the largest percentage, (57| OJ ) is found in the 

 young lower joints; the smallest, (43| ,) in ripe upper 

 straw. Only in the ear occurs a regular increase, viz., 

 from 54 to 63 | . 



4. The Albuminoids, \ in Arendt's investigation, exhibit 

 a somewhat different relation to the vegetable substance, 

 from what was observed by Bretsclmeider, as seen from 

 the subjoined comparison of the percentages found at the 

 different periods. 



Periods. 



I. II. III. IV. V. 



Arendt 20.93 11.65 10.86 13.67 14.30 



Bretschueider 22.73 17.67 17.61 15.39 



These differences may be variously accounted for. They 

 are due, in part, to the fact that Arendt analyzed only 

 large and perfect plants. Bretsclmeider, on the other 



* What remains after deducting fat and wax, albuminoids, fiber, and ash, 

 from the dry substance, is here included. 



t Calculated by multiplying the percentage of nitrogen by 6.33. 



