330 THE FLORIST AND 



and tender in their construction, afterwards they become gradually thicker, 

 more fibrous, sometimes hard as leather, dark green, and shining. Such is 

 their state in the middle of summer ; afterwards we see them lose their 

 green color, become yellow, and hang loosely down. Others become red ; 

 they acquire the particular colors that we call autumnal, and which impart 

 to the woods and pleasure-grounds, such a peculiar charm as to make us 

 loth to exchange the woods and fields for the turmoil of the town. The 

 Oak becomes brown, the black Beech whitens, the Ash loses its green 

 color, the Maple becomes yellow and black, the wild Vine of a purple color, 

 and the Cornel tree red and yellow ; the whole presents a peculiar variegated 

 mixture of the finest diversity of tints ; but all this beauty is only the pre- 

 cursor — yea, it is even the beginning of an approaching dissolution and instant 

 death. The leaves die — their whole relation to the atmosphere is changed, or 

 even seems to cease. The upper layer, by the quantity of fluid which soaks 

 through it, and of which some substances fasten on it, or affect the surface, 

 changes, thickens — but in all is at last unfit for evaporation, and shut out from 

 the air. Those regular successions in change of substances which we have no- 

 ticed as the cause of growth, as such take place no more; another series of 

 changes, in which the growth has no part, nor is even the consequence, takes 

 place instead ; external influences become, as it were, master of the body, which 

 is without the circle of life. The leaf, which is unable to discharge any more 

 substances outwardly, can take up no more, becomes a useless appendage ; 

 it soon falls from the organ of which the life is not disturbed. The fall of 

 the leaf, then, is not the consequence of the change of the seasons, for in 

 tropical countries, also, this phenomenon takes place ; it is the consequence 

 of a changed state of life itself, of the disturbed connection between evapo- 

 ration and absorption. In the month of August it was necessary, for local 

 reasons, to strip two Linden trees of all their branches. They made new 

 leaves, and they stand now (24th of November) still green and fresh, al- 

 though covered with snow, and lately there have been some severe night 

 frosts. The cause of the fall of the leaves is not to be sought for originally 

 in the atmosphere, but in the construction of those organs themselves. The 

 increased action of life is the cause of death, on account of the change it 

 brings upon the tissues, without which the leaves would not fall off, and the 

 plants we call annual, (that is, those which within the circle of a year, de- 

 velop themselves and bring forth seed) would not in so short a time die off, 

 but like shrubs and trees, would have an indefinite term of life. 



Where should we end, if we wished to continue to enumerate examples 

 of all that is to be ascribed to evaporation and its connection with ab- 



