CH. IX.] DEATH AND DECOMPOSITION. 313 



If its stem, measured just above the ground, be 

 three inches in cii'cumference, it may bear five 

 pounds weight of grapes. 



3i inches 10 lbs. 



i 15 



^ 20 



5 25 



And so five pounds additional for eveiy half inch of 

 increased circumference. 



Although fiTiit bearing is the most influential 

 curtailer of a plant's longevity, there are others of 

 scarcely less fatal efficiency, among which are im- 

 proper supplies of moisture, obnoxious soils., dele- 

 terious food, uncongenial temperatures, and deficient 

 light. These all tend to shorten a plants existence, 

 or even at once to destroy it if administered in a 

 violent or protracted degi'ee. 



Excessive moisture induces that over succulency 

 which is ever attended by weakness, unnatural 

 growth, and early decay. Such plants more than 

 any others are sufferers by sudden \acissitudes, in the 

 hygrometric state of the atmosphere, and are still 

 more fatally visited if exposed to low reductions of 

 temperature. 



Soils containing obnoxious ingredients are certain 

 introducers of disease and premature death. An 

 excess of oxide of iron, as when the roots of the 



