IDS 0?i the Anaiorny of }~e get aides ; intended to sidjstantiale 



cause of all strength and of all motion to the plant. View that 

 weak and fragile thing called the corolla of a flower: how beau- 

 tiful is each petal formed ! bat so frail, it would seem capable of 

 being destroyed by breathing on it: — and yet it will fold and re- 

 fold into difi'erer.r forms, when passing from a bud to a full- 

 Vjlown flower; will bear exposure to an evaporating atmosphere, 

 without being hurt ; will support the change of weather, rain, 

 and even a storm ; and such is its strength, that take the lovely 

 convolvulus tribe, and press the petals with }our finger, and you 

 will find a resistance beyond all conception of its force : run a 

 thread through it to prevent its folding; and if your thread is ever 

 so strong, it v/ill cither break it, or tear the CGVolla to pieces; 

 but it will by no means prevent your corolla from closing. Ex- 

 amine what causes tliis streu'^th ; dissect the stripes in which the 

 force is evidently jixed; you will find (rom fotir to seven spirals 

 concealed withni them. The petal being movopetalous, there 

 are three or four stri])es to each apparent division, and it is im- 

 possible not to see that the sirength resides in them only. What 

 astonishing force to be found in the flower of some salvias ! View 

 its high raised banner formed to defend the stamen and pistil 

 from injury; press it with your finger, it is to the stripe alone 

 it owes the preservation (;f its shape, the force it possesses. This 

 flower has strength enough to oppose a young hornet. I saw the 

 ecarlet salvia attacked by one; it had entered the flower, and was 

 attempting to reach the secret nectary below; but it was very 

 near paying with life for its temerity ; for, having inserted its head 

 and shoulders within the inward l)end of the petals, they were 

 visibly contracting, and began to close above, and in a few mi- 

 nutes the creature would certainly have been drowned ; for the 

 juice within increased each moment, pressed up from the secret 

 nectary below: — it was just dead when I took it out, but soon 

 revived enough to l)e dangerous. It is certain that many flowers 

 have the power of defending their secret nectary by closing; since 

 during my constant watching of plants I have several times found 

 insects thus confined ; the muscle thus contracting from the 

 heat of the insect's body, which has quite caloric suBicient to in- 

 fluence a spiral wire, though perhaps not our thermometers*. 

 The force of the spiral is not only discovered in the flower, but 

 .still more in the leaf, as the whole health of the plant depends 

 on the constant motion of the leaves of the trees, u-hich merits 

 them the name of lungs to the plant, though they have few or 

 no air-vessels within them: but the constant motion in which 



* The insects, feel cold to as, because tliey arc so iiifinitfly colder tliaii 

 our skin ; niul we feel the cold, because we part with so mucli heat to theui; 

 liiit in reality it has more Nvaruitli than the vegetable even during Iructirt- 

 jation — :is 1 bliall show in my neit letter. 



the 



