78 VITAL ACTIONS. 



are among the most perishable ; starchy seeds, which 

 are least subject to change, are the most tenacious of 

 life. 



103. Warmth, moisture, and an excess of oxygen, 

 but especially -warmth and moisture, while they are 

 the greatest causes of germination, are probably, on 

 that same account, the chief causes of death. Seeds 

 remain dormant so long as the proportion of carbon 

 peculiar to them is undiminished; water is decom- 

 posed by their vital force (14) ; and its oxygen, com- 

 bining with the carbon, forms carbonic acid, which 

 is given off. The effect of access of water is, there- 

 fore, to rob seeds of their carbon; and the effect 

 of destroying their carbon is to deprive them of the 

 principal means which they possess of preserving 

 their vitality. 



104. Although a seed, if fully formed, is in all 

 cases capable of perpetuating its race, yet there is 

 a difference in the degree to which this capability 

 extends. All seeds will not equally produce vigor- 

 ous seedlings : but the healthiness of the new plant 

 will correspond with that of the seed from which it 

 sprang. For this reason, it is not sufficient to sow a 

 seed to obtain a given plant : but, in all cases where 

 any importance is attached to the result, the plumpest 

 and heaviest seeds should be selected, if the greatest 

 vigour is required in the seedling ; and feeble or less 

 perfectly formed seeds, when it is desirable to check 

 natural luxuriance. It is apparently for this reason, 

 that old Melon seed is preferred to new; for the 

 latter would give birth to plants too luxuriant for 



