During this growth, during this transition from the shrub to the young tree, with a separate and upright stem, a new being has been formed. Organs which it had not have come to it, and have made it a separate individual. It has flowers, it has branches, it has new vessels for the circulation of the sap, and the juices which were not previously elaborated. The structure of the surface of its leaves has been changed, so that absorption may be more successfully accomplished. Where is the shoot, from which our vigorous young shrub sprung? What relation, what resemblance is there between these two beings? We can only discern differences. One individual has succeeded to another individual. The vegetable has been renewed, not only in matter, which is changed, but in the form of its organs. A series of new forms have succeeded each other in the shrub, since it was a simple shoot, just peeping above the soil. It is still the history of change, when the young tree has become adult, when, in the progress of years, its trunk has grown hard, and become incrusted with layers of accumulated bark, when its branches have multiplied, and flowering and fruitage have modified all its internal and external parts. It is then a grand cedar tree, whose majestic and imposing shade covers a considerable extent of the soil; or a superb oak, whose robust and gnarled branches spread far and wide; or a flexible chestnut, which flings about its polished and shining arms. The organs of these luxuriant vegetables, the pride of our forests, have no relation to those which belonged to them in the first years of their life. Their flowery crowns in spring-tide, the fruits which succeed to them, the seeds shut up in the protecting shelter of those fruits, these are all peculiarities of organization, belonging to these noble trees, without any analogy in nature. Where is the grain of mustard seed which formerly sucked the juice of the earth in darkness? Everything is changed; the place of habitation, which is no longer the earth, but the air; the form, and the physiological functions. Not only has all this changed, but it has changed a great number of times. Not only does nothing remain of the matter of which the tree was composed in the earlier stages of its life, but nothing has been retained of the organic forms which were proper to the infancy of the vegetable.