COMPOSITION IN SUCCESSIVE STAGES. 215 



tion of this substance, probably clue to unavoidable loss 

 of lower leaves, but not to a resorption or metamorphosis 

 in the plant. 



3* Fat is formed most largely at the time of blossom. It 

 ceases to be produced some weeks before ripening. 



4, The formation of Albuminoids is irregular. The 

 greatest amount is organized during the 4th period, (after 

 blossoming.) The gain in albuminoids within this period 

 is two-fifths of the total amount found in the ripe plant, 

 and also is nearly two-fifths of the entire gain of organic 

 substance in the same period. The absolute amount or- 

 ganized in the 1st period is not much less than in the 4th, 

 but in the 2d, 3d, and 5th periods, the quantities are con- 

 siderably smaller. 



Bretschneider gives the data for comparing the produc- 

 tion of albuminoids in the oat crop examined by him with 

 Arendt's results. Taking the quantity found at the con- 

 clusion of the 1st period as 100, the amounts gained during 

 the subsequent periods are related as follows : 



PERIODS. 



I. II. III. (IE & III.) IV. (II, III & IV.) V. 



Arendt 100 67 46 (113) 120 (233) 36 



Bretschneider ...100 ? ? (165) 63 (227) 35 



We perceive striking differences in the comparison. In 

 Bretschneider' s crop, the increase of albuminoids goes on 

 most rapidly in the 3d period, and sinks rapidly during 

 the time when in Arendt's plants it attained the maximum. 

 Curiously enough, the gain in the 2d, 3d, and 4th periods, 

 taken together, is in botli cases as good as identical, (233 

 and 227,) and the gain during the last period is also equal. 

 This coincidence is doubtless, however, merely accidental. 

 Comparisons with other crops of oats,examined,though very 

 incompletely, by Stockhardt, (Chemischer Ackersmann, 

 1855,) and Wolff, (Die Erschopfung des Bodens durch die 

 Cultur, 1856,) demonstrate that the rate of assimilation is 

 not related to any special times or periods of development , 



