COMPOSITION ET SUCCESSIVE STAGES. 209 



first stages of ripening, but falls off at last to minimum. 

 The ratio of Oxygen to Carbon is the same during the 1st 

 and 3d periods, but increases remarkably from the period 

 of full blossom until the plant is ripe. 



As already stated, the largest absolute assimilation of 

 all ingredients — most rapid growth — takes place at the 

 time of heading out, or blossom. At this period all the 

 volatile elements are assimilated at a nearly equal rate, 

 and at a rate eqiaal to that at which the fixed matters (ash) 

 are absorbed. In the first period Nitrogen and Ash ; in 

 the fourth period Nitrogen and Oxygen; in the fifth pe- 

 riod Oxygen and Ash are assimilated in largest propor- 

 tion. 



This is made evident by calculating for each period the 

 Daily Increase of Each Ingredient, the amount of the in- 

 gredients in the ripe plant being assumed at 100 as a point 

 of comparison. The figures resulting from such a calcula- 

 tion are given in 



Table IX.— Br. 



The increased assimilation of the 5th over the 4th period 

 is, in all probability, only apparent. The results of anal- 

 ysis, as before mentioned, refer only to those parts of the 

 plant that are above ground. The activity of the foliage 

 in gathering food from the atmosphere is doubtless greatly 

 diminished before the plant ripens, as evidenced by the 

 leaves turning yellow and losing water of vegetation. 

 The increase of weight in the plant above ground probably 

 proceeds from matters previously stored in the roots, which 

 now are transferred to the fruit and foliage, and maintain 

 the growth of these parts after their power of assimilating 

 inorganic food (CO,, H,0, NH,, N.OJ is lost. 



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