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same manner as the particles of soil do, and catch the particles 

 of water, whether in the fluid form, as from rain ; or they can 

 condense aqueous vapour just as the particles of the soil can do, 

 and in this manner they will draw from the air supplies of 

 watery vapour sufficient for the closed cells of the root with 

 which they are in contact, for the plant in this case is absolutely 

 dependent on the water which is thus taken up. It is, no doubt, 

 a matter of common observation that drooping plants recover 

 their turgidity when they are wetted by dew or rain, or if the 

 air be moist. This is the result, however, partly of an in- 

 creased supply of water from the moistened earth, and partly 

 of a diminished transpiration in consequence of the dampness 

 of the atmosphere : — it is not the result of absorption of water 

 by the leaves. 



This phenomenon of drooping or withering occurs con- 

 spicuously in parts of plants which have been cut off in air. 

 Thus, if we cut through the stem of a Sunflower (Helianthus 

 annuus) or of the Birth wort (Aristo lochia Sifiho) and place it 

 in water in such a manner that the cut surface and the water 

 are in contact while the leaves are in the air, and then expose 

 it to the daylight, we soon find that the water sucked up by 

 the cut surface is not a sufficient quantity to compensate for 

 the loss of watery vapour taking place by evaporation from the 

 leaves, and the plant therefore, after a short time, droops and 

 withers ; — cut flowers also soon become withered, shrivelled and 

 flaccid through loss of water when exposed. This experiment 

 shows us that the younger terminal leaf-bearing portions of the 

 stems of plants which have large leaves, and consequently a large 

 surface for evaporation, when they are cut off in air, partially 

 lose the power of conducting water. The withered shoots of 

 flowers, however, may be revived in a short time by forcing in 

 water under pressure. 



For this purpose, a u shaped bent glass tube is taken and 

 filled with water, the stalk of the withered shoot is then passed 

 through a perforated stopper of caoutchouc, and this is then 

 fixed on to one end of the U tube, in such a manner as to be 

 perfectly air-tight. Mercury is then poured in at the opposite 



