Notes and Gleanings. i8i 



Vegetable Transpiration and Sensitiveness. — A gardener who studies 

 Nature, and gives his mind to chemistry, botany, &c., can tell us something that 

 relates to plant-life and to vegetation generally in its relations to the elements. 

 In fact, a cultivator has the best of opportunities to become a philosopher, if he 

 will. I verily believe that a gardener's calling is one of the best, in spite of the 

 low rate of wages, because of the enjoyments that accompany it, and the stimu- 

 lus it affords to thought and observation. However, let us pass as quickly as 

 possible to the subject of this paper. 



Every cultivator is aware that evaporation takes place in plants to an incon- 

 ceivable degree in certain circumstances. It is known by the experiments of 

 Dr. Hales (Statical Essays) that a sunflower will lose as much as a pound and 

 fourteen ounces by perspiration in twelve hours, and that, in general, a sunflower 

 perspires seventeen times more than a man. The same accurate observer found 

 that a cabbage perspired in twelve hours a pound and nine ounces ; a paradise 

 stock in a pot eleven ounces ; and a lemon-plant eight ounces. Guettard states 

 that he found C^r;/«j- ;/z<2j-(:?//rt: perspire twice its own weight in one day; and 

 Mr. Knight remarked once, that a vine lost moisture in a hot day with such 

 rapidity, that a glass placed under one of its leaves was speedily covered with 

 dew, and in half an hour the perspiratron was running down the glass. In damp 

 weather, evaporation is the least ; in hot, dry weather, it is the most. The loss 

 which results must be supplied by the moisture introduced into the system by 

 the spongioles ; and, therefore, if we destroy the spongioles, evaporation cannot 

 take place until they are replaced, and. of course, the plant must necessarily 

 make a struggle for life, or die. This is undoubtedly the reason why we cannot 

 remove deciduous trees when in leaf, for it is impossible to remove them without 

 injuring their spongioles ; and it must be equally impossible to prevent the evap- 

 oration from their leaves : this evaporation e.xhausts them of their sap, and the 

 roots afford no help to keep up the supply, and death follows. When they are 

 kept in pots, it matters not at what season their removal takes place, because, as 

 their spongioles are then uninjured, if they are planted out with proper care, 

 even excessive evaporation would be made good by the action of the roots. 

 Moreover, we can give them the advantage of shading, frequent sprinkling. &c. 



It is a well-known fact to most of us that certain evergreens, such as hollies, 

 laurels, &c., can be transplanted in almost any month. This must arise from 

 their perspiration being much less copious than is the case with deciduous trees; 

 wherefore the spongioles have less difficulty in supplying the loss occasioned by 

 it. Yet even evergreens cannot be removed in the hottest months of the year 

 with impunity, because then the action of such spongioles as may be saved in 

 the operation would not be sufficient to supply the waste by evaporation. Now, 

 if deciduous trees are taken from the ground in the summer, and are potted and 

 then plunged into a hotbed to recover themselves, not for the sake of the heat, out 

 because the atmosphere of a hotbed is so charged with humidity, that perspira- 

 tion cannot go on, their lives may be saved, and in the end they may be little 

 the worse for the operation. The vital energies of the plant, instead of being 

 wasted by evaporation, are directed to the formation of new roots, or new mouths 

 by which to feed ; and theory and practice are conjoined in their preservation. I 



