COMPOSITION IN SUCCESSIVE STAGES. 235 



Bretschneider's crop the increase of albuminoids goes on 

 most rapidly in the 3d and 3d Periods, and sinks rapidly 

 during the time when in Arendt's plants it attained the 

 maximum. Curiously enough, the gain in the 3d, 3d 

 and 4th Periods, taken together, is in both cases as good 

 as identical (233 and 227), and the gain during the last 

 period is also equal. This coincidence is doubtless, how- 

 ever, merely accidental. Comparisons with other crops 

 of oats examined, though much less completely, 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, but 

 depends upon the stores of food accessible to the plant 

 and the favor of the weather, or other external conditions. 



The following figures, which exhibit for each period 

 of both crops a comparison of the gain in albuminoids 

 with the increase of the other organic matters, further 

 strikingly demonstrate that, in the act of organization, 

 the nitrogenous principles have no close quantitative 

 relations to the non-nitrogenous bodies (carbhydrates 

 and fats). 



The quantities of albuminoids gained during each 

 period being represented by 10, the amounts of carbhy- 

 drates, etc., are seen from the subjoined ratios : 



PERIODS. 



Ratio in 

 I. II & III. IV. V. Ripe Plant. 



Arendt 10:34 10:114 10:28 10 : 25 10:66 



Bretschneider..lO : 30 10 : 50 10 : 46 10 : 120 10 : 51 



5. The Ash-ingredients of the oat are absorbed through- 

 out its entire growth, but in regularly diminishing quan- 

 tity. The gain during the 1st Period being taken at 10, 

 that in the 2d Period is 9, in the 3d, 8, in the 4th, 5, 

 in the 5th, 2 nearly. 



The ratios of gain in ash -ingredients to that in entire 

 dry substance, are as follows, ash-ingredients being 

 assumed as 1, in the successive periods : 



