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Textes en anglaisLyell, Charles, Principles of Geology (extract of Vol. 2) • CHAPTER II.
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THE theory of the transmutation of species, considered in the last chapter, has 
met with some degree of favour from many naturalists, from their desire to 
dispense, as far as possible, with the repeated intervention of a First Cause, 
as often as geological monuments attest the successive appearance of new races 
of animals and plants, and the extinction of those pre-existing. But, 
independently of a predisposition to account, if possible, for a series of 
changes in the organic world, by the regular action of secondary causes, we have 
seen that many perplexing difficulties present themselves to one who attempts to 
establish the nature and the reality of the specific character. And if once 
there appears ground of reasonable doubt, in regard to the constancy of species, 
the amount of transformation which they are capable of undergoing, may seem to 
resolve itself into a mere question of the quantity of time assigned to the past 
duration of animate existence.

Before we enter upon our reasons for rejecting Lamarck's hypothesis, we shall 
recapitulate, in a few words, the phenomena, and the whole train of thought, by 
which we conceive it to have been suggested, and which have gained for this and 
analogous theories, both in ancient and modern times, a considerable number of 

In the first place, the various groups into which plants and
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Auteur et directeur de publication : Pietro CORSI,
Hébergement : Centre de Calcul de l'IN2P3-CNRS.