464 CHARACTER OF VEGETABLE VITALITY. CHAP. XI. 



fluid, after the sentient principle is gone ? Is not the 

 submersion of the Water Lily during the night, if 

 such is the fact, the result merely of the shrinking 

 of the stem, in the absence of light and warmth ? or 

 of an alteration in the specific gravity of the flower, 

 in consequence of the folding in of the petals ? Is 

 not the emerging of the male flowers of the Valis- 

 neria at the period of impregnation, as well as the 

 subsequent sinking down of the female flower, to be 

 attributed to the same cause ? And is not the ex- 

 pansion of the petals during the day, and their shut- 

 ting up during the night, as well as also the muta- 

 tion of the plant, to be attributed merely to the 

 chemical action of light and heat operating upon 

 the fibres, or vital principle of the plant, as was 

 supposed by Hales ? If these causes are sufficient 

 to account for the effects in question, then it would 

 be altogether unphilosophical to allege the agency 

 of a higher cause. 



Hedysa- But one of the strongest indications of the ex- 

 istence of a species of sensitive principle in the plant 

 is perhaps that which is exhibited in the case of 

 Hedysarum gyrans. This plant is a native of 

 India, and grows on the banks of the Ganges, its 

 leaves are ternate, the middle leafit being larger, 

 and the lateral leafits smaller. All of them are in 

 perpetual motion up and down, sometimes equably 

 and sometimes by jerks, but without any unison be- 

 tween each other; the motion being always the 

 most distinct and most rapid in the lateral leafits. 



